Projection tower-3D
输电线路铁塔三维数字化建模方法研究
输电线路铁塔三维数字化建模方法研究李美峰,冯勇,许泳,黎亮,黄兴(西南电力设计院有限公司,四川成都610021)摘要:输电线路工程正在大力推进三维数字化和智能电网的建设,实现对设备设施全寿命周期的管理。
但目前针对铁塔的三维数字化建模方法暂无系统性研究。
对铁塔三维数字化模型进行定义,分析模型细节层次,总结和分析目前主要的建模方法及优缺点,提出了一种从铁塔计算模型直接生成三维实体模型的建模方法,从而构建满足全寿命周期管理的铁塔模型。
梳理现有铁塔三维数字化建模通用软件的优缺点,采用Tekla Structures软件,建立一种特高压工程铁塔三维模型。
关键词:铁塔;三维数字化模型;建模方法中图分类号:TM75文献标志码:A文章编号:1007-9904(2019)07-0018-06 Study on the Method of Three-dimensional Digital TowerModel for Overhead Transmission LinesLI Meifeng,FENG Yong,XU Yong,LI Liang,HUANG Xing(Southwest Electirc Power Design Institute Co.,Ltd.,Chengdu610021,China)Abstract:The construction of three-dimensional digitalization and smart grid is promoted vigorously in transmission line projects to achieve the life-span management of the equipment and facilities.However,there is no systematic study on the modeling method of the three-dimensional digital tower model.In this paper,the content that a three-dimensional digital model of the tower should include is defined.The levels of the model detail is analyzed.The modeling processes via different methods are compared.A method is proposed that could directly generate the three-dimensional solid model from the calculation model, thus a life cycle management model can be constructed.On the basis of evaluating the existing general software been used for three-dimensional digital modeling of steel tower,Tekla Structures software is used for the modeling of a three-dimensional tower model of the ultra-high-voltage project.Keywords:transmission tower;three-dimensional digital model;modeling method0引言近年来,建筑信息模型化(Building Information Modeling,BIM)技术在建筑、水力、化工、石油等行业进入应用阶段,但在输电线路行业尚处于探索阶段。
基于微机的塔台管制模拟系统中三维场景的建立
维普资讯
第 ２ Ｏ卷 第 ３期
中 国 民 航 学 院 学 报
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(整理)2D转3D立体电影之模型重建技术.
2D转3D立体电影之模型重建技术（上海动影传媒2D转3D立体原创技术文章）2D转3D立体有不同的方案可以实现，最终效果当然也是参差不齐，目前的2D转3D立体效果最好的当属模型重建技术。
所谓模型重建技术，就是还原拍摄画面的场景后，将画面中的元素进行建模处理，类似maya、max 之类的三维软件建模，形成真正具有Z轴纵深的三维图像，而不是在二维的平面图上处理。
这样转换的优势非常明显，还原成模型之后可以随意的进行调整，灵活度较大而且效果最为逼真。
简单来讲，还原成模型之后，等同于在现场进行实拍，甚至是超越实拍所受限制，形成较为出色的3D立体效果。
还是以好莱坞大片《指环王3》做演示，在这段视频中是一个人物特写，我们通过特写来表现模型重建的效果。
图1是原始2D画面，这个画面的层次比较少，背景基本上没有什么元素，不能与人物形成较大反差，这类图像在进行2D转3D立体的时候比较棘手，因为缺少丰富的层次，立体感就行对较弱。
针对这幅图像，我们把重点放在人物上，将人物调节的更为饱满，配合身上的盔甲形成明显的层次。
图2是转制后的效果，可以看出身上的盔甲层次比较明显，整个画面立体感并不弱，看上去也是比较舒服的。
对于人物的面部没有进行过多处理，怕影响了人物的原型，只是对鼻子、下巴部分进行了处理，使之凸于面部并与鼻梁护甲形成纵深过渡。
由于是特写画面，那么就对盔甲的层次、盔甲上面纹饰的细节进行了重点处理。
图4是模型重建后的基本形状，在此基础上对细节进行更为细致的调节。
图5中是模型左侧视图，可以看出人物面部的浮雕拉伸效果，可以明显看出下巴部分也是凸向于镜头的。
图6是模型右侧视图，可以明显看出右肩膀护甲上面的纹饰被刻意加强，而纹饰左侧的小圆钉却是凹与镜头方向。
图7是模型左侧视图，可以明显看出左肩膀护甲上面的纹饰被刻意加强，而纹饰右侧的小圆钉却是凸与镜头方向。
图8是人物领口部分，可以看A位置的护甲也被进行了浮雕拉伸，而B位置的纹饰也被加强。
三维重建十大品牌简介
自动化程度高：可以自动识别和重建各种类型的对象和场 景。
高精度：采用先进的算法和技术，能够实现高精度的三维 重建。
应用领域：汽车、航空航天、国 防、建筑、文化遗产等。
• 汽车行业：为多家汽车制造商 提供三维扫描和模型重建服务 ，用于产品设计、质量检测和 制造过程优化。
• 文化遗产：合作修复和维护世 界各地历史遗迹，为其提供三 维数据记录和可视化工具。
07
品牌七：Trimble SketchUp 3D Wareho
05
品牌五：FARO Scene 3D
公司简介
• FARO Scene 3D是一家总部位于美国的计算机视觉和3D技术公司，成立于1990年代。该公司以其在3D测量 、建模、渲染和可视化方面的专业技术和产品而闻名，是三维重建领域的知名企业之一。
产品线及特点
• FARO Scene 3D主要产品包括3D激光扫描仪、软件和配套的云服务。其软件 可以快速将3D激光扫描数据转化为高质量的3D模型，具有自动化、高效和高 精度的特点。此外，FARO Scene 3D还提供一系列的附加工具和服务，如渲 染、测量和分析工具等，以帮助用户更好地利用其3D数据。
产品线及特点
• Leica 3D的产品线涵盖了各种类型的3D测量设备，包括手 持式、桌面式、在线式等。其手持式设备采用非接触式激光 扫描技术，能够快速、准确地获取物体表面的三维数据。桌 面式设备则适用于小型的物体或场景，如文物、模具等。在 线式设备则用于生产线上的实时测量和质量控制。此外， Leica 3D还提供了一系列的后处理软件，可以对获取的三维 数据进行处理、分析和输出。
• NextEngine 3D Modeler： 专注于复杂三维模型重建和数 据可视化的软件平台，具备强 大的点云处理和三维建模功能 。
GodWork空三软件用户手册
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6.2.11 只显示细节窗口..................................................................错误！未定义书签。
5.3 精确匹配...........................................................................................错误！未定义书签。
5.4 灰度点优化.......................................................................................................................19
3 天工航空影像空中三角测量软件工作流程.........................................................................13
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6.2.8 多影像缩小............................................................................错误！未定义书签。
犀牛指令集
绘制与一曲线成切线的线段。 LineTT 绘制与二次曲线成切线的线段。 LineV 绘制与设计平面垂直的线段。 List 列出物件的设计资料。 Lock 锁定物体。 LockOsnap 锁住物体的捕捉功能。 Loft 放样曲面。 Make2D 将立体物体转绘成平面图。 MakeCrvPeriodic 将开放的线段封闭，或者将已封 闭曲线平滑化 MakeSrfNonPeriodic 将曲面变成可以产生节点的曲面 。akeSrfPeriodic M 将开放的曲面封闭，或者将已封 闭曲面平滑化 Match 两曲线端点靠齐。 MatchLayer 将选择的对象移动到另一层。 MatchSrf 将两个不相连曲面的边缘拉靠在 一起。 MaxViewport 最大化视图显示。 MergeEdge 连接曲面上相邻的两边缘。 MergeSrf 连接二相邻未经修剪得曲面。 Mesh 将NURBS对象转换成网格物体 。eshBox M 绘制多边形网格立方体。 MeshCone 绘制多边形网格圆锥体。 MeshCylinder 绘制多边形网格圆柱体。 MeshDensity 改变多边形网格的密度。 MeshPlane 绘制多边形网格平面。 MeshPolyline 从一封闭多边形曲线建立多边形 网格。
Polygon 绘制多边形。 PolygonEdge 以一边绘制多边形。 Polyline 以选择的点建立线段。 PolylineOnMesh PolylineThroughPt 以选择的点建立线段。 PrevU 选择U坐标上的一个控制点。 PrevV 选择V坐标上的一个控制点。 Print 打印。 PrintSetup 打印摄制。 Project 投射一曲线至曲面上。 Projection 切换视图为等角视图或透视图。 ProjectOsnap 投射物体捕捉的点至设计平面上 。 ProjectToCPlane 投射物体至设计平面上。 Properties 编辑物体属性。 Pt 捕捉点。 PtOff 关闭显示控制点和编辑点。 PtOn 打开显示控制点和编辑点。 Pull 依靠近的部位将曲线拉至曲面上 。 Quad 捕捉圆或椭圆的四个点。 Radius 测量弧的半径。 RaliRevolve 将一曲线沿着一轨道与轴心旋转 成型。 ReadCommandFile 从外部文档读取命令文件。 ReadNamedCPlanesFromFile 读取已命名的视图或设计平面。 ReadViewportsFromFile 从外部3DM文件读进视区。 RebuildEdges 重建曲面边缘的组成架构。 RebuildSrf
用3D打印技术建造摩天大楼
用3D打印技术建造摩天大楼作者：来源：《时代英语·高三》2017年第05期Many of the world’s tallest skyscrapers will make you queasy if you reached their summit. But these grand buildings could soon look like a bungalow in comparison to a three-mile high skyscraper envisioned by architects.They say that the mighty tower could be built by 2062， using 3D printing technology to create walls that could withstand high winds and unique climates.The skyscraper is the vision of Arconic， a materials science company based in New York， as part of its larger campaign called The Jetsons — an homage to the 1962 cartoon， set in 2062.Engineers from the firm are working with futurists to imagine how the world will look in 45 years.The team has envisioned the Arconic tower — a three-mile-high skyscraper created using materials that are either in-development or have already been brought to market.As well as being staggeringly tall， the tower will also have futuristic features， including smog-eating surfaces， and retractable balconies.Arconic is currently working on a project called EcoClean， a special coating that allows building to self-clean and purify the surrounding air.Sherri McCleary，one of Arconic’s chief materials scientists， told Business Insider，“The functional coating provides aesthetics， it provides maintenance benefits， and it also provides a benefit to the surrounding environment by reducing the content of pollutants around it.”如果你到過世界许多摩天大楼的最高层，你一定头晕目眩过。
3D立体影像 - 山顶的老照片复活技术
数码时尚美容中心？个性化布TransferHC网络的丝网印刷特殊印刷行业频道丽卡的超时空要塞3D技术了独特的“边缘优化和三维数据的计算，”设计的三维曲面过渡自然，流畅，真实的，之前和之后的结构化，完全去除片感，可以修改任意三维图像，直到您满意为止。另外，因为只是普通的平面图像，所以图像信号源，图像质量，技术控制，拍摄方便，视差控制，取决于数量上的障碍，在传统的立体电影无法比拟的优势。人们惊叹数码科技的同时，深广阔的市场前景，这项技术为他们进军应用：摄影业：婚纱摄影，人像照片，风景摄影等广告行业：灯箱广告，海报等，室内：装饰画，景子屏幕等;展览：网站设计，展板，建筑效果图，三维标志等;文物古董珍品仿真，产品表示损失;城市景观：一个明亮项目，建筑装饰，印刷行业：日历，日历，装饰画，明星卡，贺卡等;三维设计：专业的广告机构提供全景改造设计;照明照明：三维灯，立体壁灯纪念雕塑：新概念虚拟纪念馆sculpture.Science的是更方便，更三维cheaperThree图像捕捉技术出现在上世纪九十年代初，这项技术的问世，在摄影史上划时代的significance.A多拍三维相机轻松拍出几万元的价格让人望而却步，更何况普通的摄影师，即使是专业摄影师“长机”有一点，以吸引购房者。因此，长期的机厂家高薪的工作结束，双方都抱着到庆祝streets.Worth是一个具有里程碑意义的立体照片拍摄于2005年8月的技术可丽卡的诞生。究其原因，这种薄膜技术是一个划时代的立体电影技术，率先使用这种方法，只有一个简单的轨道，它可以是任何普通的数码相机完成立体摄影和拍摄作为铁路爆发滑动式镜头数量的限制后，三维成像优于几万元，但也充满生动的长machine.To丽卡所有不锈钢拍摄指南，是一家综合性的国内和国外类似的诸多优点的基础上，繁就简，改进，经过反复优化的创新产品。尤其是距离链接推力型结构可以灵活调整，在使用中，使用后方便不锈钢collection.Powerful所有组件，精细灵巧，结构flexibility.simple，科学合理的设计。实用，耐用，容易use.can成一个三维摄像笔是任何普通的数码相机，采用了高超出今天的多镜头立体plete一个小镜头，多摄像头，甚至100个镜头无限实现shooting.can近景，中景，拍摄立体视觉barrier.whether的拍摄对象是静物，风景，或人可能需要几分钟到complete.synthesis软件界面清晰，操作简单，三维合成快速，流畅，perfect.Virgin市场价值的的无限potentialOnce掌握立体摄影技术指南，你可以实现所有现场拍摄的图片全部立体效果的梦想，但也因为你的技术，节省了高昂的生产成本，不计成本，你可以设计，无所顾忌膜。握住剑在科学和技术可以是一个漫长的直入三维摄影行业，页脚，立体广告，立体牌匾行业，立体卡行业，三维立体印刷工艺品制造产业。
游戏引擎名称
开源2D引擎：∙cocos2d∙d2d∙ika∙AGen∙gosu∙Mokoi Gaming∙LOVE∙Gosu∙PTK∙Thousand Parsec∙PPTactical Engine∙elf2d∙Daimonin MMORPG∙Blackthorn∙lastexpressengine∙tamy∙stardust∙ruge∙MAGE∙Edge Game Engine∙Orx∙chingu(Ruby)∙HGE∙FlatRedBall∙DxIce∙exgine（dephi）∙Entropia∙OSARE∙ProtoEngine（Javascript）∙mofe∙tonk(Python)∙Bismuth Engine∙retroremakes-framework∙scage（Scala）∙ArcLib∙tIDE∙flamingoengine(Python)∙Ethanon∙angel engine∙FIFE project∙Novashell∙Weaver(Linux)∙verge 3∙GTGEArcEngine开源3D游戏引擎∙Ogre∙Crystal Space∙Delta3D∙Irrlicht Engine∙CHAI 3D∙Cafu Engine∙ZFXCEngine∙Q3Viewer∙Drag[en]gine∙DUMB(Linux)∙DXQuake3∙Brume∙Open Toolkit∙RaydiumEn∙PySoy （Python）∙pygame（Python）∙BlendELF∙Ambrose3D∙AgateLib（.NET）∙D’Enfent Engine∙Asphyre Sphinx(Delphi)∙pyggel（Python）∙NeoEngine∙Horde3D∙ika∙Lightfeather∙syBR Engine∙SoftPixel Engine∙SED∙RomantiqueX(XNA)∙GLOBE_3D∙NeL Engine∙NewWorld3D∙M0TE∙MUD Designer(C#)∙Muli3D∙Linderdaum∙Lilith3D(Geo-Morphing)∙Entropia Engine∙SxDL∙APOCALYX 3D Engine ∙Genesis3D∙QuakeForge∙NetGore (C#)∙Stratagus∙SDL∙PLIB∙ClanLib SDK∙GLFW∙Allegro∙3DzzD∙Jad Engine (C#)∙Agar∙6DX 3D Engine∙OSG∙Cube 2: Sauerbraten ∙SCEngine∙vbGORE∙TNT Basic∙nebula3∙Sphere RPG engine.∙GhostEngine∙Hazy Mind（XNA）∙nagine3d∙mako engine∙aeon3d∙mcore3d∙tubras∙mgep∙Sylphis3D∙Yage∙XreaL∙Q 2.0∙Quesa∙Reactor3D(XNA)∙Metrolog Xg∙plush∙Lystra Engine∙LightFire(C#)∙LEAF2∙Lightning Engine∙jMeteor∙QBasic∙Lightspeed 3D(MacOS)∙Protea∙Original3D∙Purple#∙Cat Mother∙ExoEngine∙Poly Engine∙XEngine∙Xvizn∙Yake∙OpenSpace3D∙rgdengine∙ezrpg（PHP）∙glueengine(C#)∙G3DRuby∙netgore(C#)∙fosengine∙u-nebula∙renderengine（JavaScript）∙ltegameengine∙axonengine∙jgge∙Espresso3D∙RetinaX∙Reality Factory∙gmogre3d∙prequengine∙Epee Engine∙Axiom 3D Engine∙G3D∙OHRRPGCE∙Open Game Engine∙Baja Engine∙Blender∙Irmo∙Xith3D∙Soya 3D（Python）∙Panda3D∙Quake Engine3∙Quake Engine2∙AmaltheiaQuake Engine商业通用游戏引擎：∙∙Unreal ENGINE3∙CryENGINE3∙Gamebryo∙Vision Engine∙unity3d∙Source Engine∙Shiva 3D∙Unigine∙Torque 3D∙C4 Engine∙Truevision3D∙Demoniak3D∙CSP engine license∙Codecreatures∙Buzz 3D∙3DSTATE∙Antiryad Gx∙Glacier∙Esperient Creator∙Lucid∙ludiloom∙Luxinia∙LawMaker∙GameStart∙Glint 3D ScriptENGINE∙Esenthel Engine∙GameCore∙Nowhere Engine∙S2Engine∙Quest3D∙Exocortex∙Frame Simulator∙Codecreatures∙worldaxis3d∙Xors3d∙VRcontext∙CPAL3D∙Ready At Dawn Engine∙Nytro Game Engine∙game start3d∙Visual3D Game Engine∙Vicious Cycle Software∙MetaVR∙Grualia Game Engine∙Gamestudio∙BlitzMax∙Cipher Game Engine∙Visual3D Game Engine∙Wild Pockets∙3DVIA Virtools∙Vicious Engine∙VATAN ENGINE∙Cobra 3D engine(Cobra )∙Qube Software∙FreshEngine（PSP）∙Shark 3D∙eye-sys∙NeoAxis Game Engine∙DX Studio∙3DVIA Virtools∙Agency9Abyssal Engine商业MMO游戏引擎：∙Hero ENGINE∙Realm Crafter∙Zythum-Project∙Bigworld∙Chaos Game Engine∙Prime EngineMultiverseAndroid 2D开源游戏引擎：∙∙AGE∙Angle∙cloak∙Cocos2D∙juicygames∙libgdx∙Rokon∙mages∙candroid engineandengineAndroid商业游戏引擎：∙Roar EngineAndroid 3D开源游戏引擎：∙∙catcake∙jPCT-AE∙kwaak3∙Gamine∙Alien3D∙forget3dPapayaiPhone商业游戏引擎：∙∙airplaysdk∙PlaytoTv∙Kanji∙Shiva Ston3d∙iTGE∙Bork 3D∙Unity For iPhone∙GameSaladiXors3diPhone开源引擎：∙∙galaxyengine∙gamekit∙Oolong∙SIO2∙chipmunk-physics∙card-surface∙Tec engine。
舞台英文术语
Personnel 员工Production Team 制作队executive producer 执行制作人director 导演musical director 音乐总监choreographer 编舞者technical director 技术总监stage designer 舞台设计师production property master 道具负责人sound designer 音响设计师costume designer 服装设计师lighting designer 灯光设计师scenic designer 布景设计师scripter writer 编剧作家poser 作曲家production carpenter 制作木工production electrician 制作电工production supervisor 制作监视员publicist 公关Administrative Team 行政队pany representative 公司代表pany manager 公司经理union representative 工会代表production manager 制作经理business manager 业务经理publicist 宣传人员legal counsel 法律参谋Running Crewstage hand 舞台工作人员stage crew 舞台工作人员light board operator 灯光控制盘操作者head electrician 电工领队head fly man 吊杆操作领队riggers 吊杆操作者fly man 吊杆操作者projectionist 放映人员flyboy 吊杆操作者gofer 杂事的职员prompter 提词人scene shift 搬移道具人员Performersnegative characterchorus 合唱曲组员artist 艺人understudy 替角antagonist 主要演员protagonist 第二主要演员principal 主要演员supernumerary 编外演员joker 丑角orchestra 乐团music conductor 音乐指挥master of ceremony 司仪double cast 双复演员Backstage Crew 后台人员property crew 道具人员makeup artist 化装师gopher 跑腿wardrobe manager 衣箱经理Hair (Person) 头发师Lobby Crew 前台工作人员House manager 前台负责人usher 剧场引座员house crew 剧场工作人员ticket collector 收票员patron 赞助者Lighting 灯光Production Team 灯光制作队Lighting Designer 灯光设计师Assistant Designer 助理灯光设计师Lighting Board Programmer/Operator 灯光控制盘操作者Master Electrician 电工负责人Electric crew 电工Electric 电Electric Current/circuitry 电流/电路open circuit 开路panic switch 恐慌开关alternating current (~)(AC) 交流电3-phrase current 三箱Amp/Ampere 安培circuit (elec.) 电路circuit breaker 断路器pany switch, auxiliary power source 辅助电源connect (to) (with, up) 连接connected in parallel 并联connected in series 并联current (el) (A) 电流direct current (DC, =) 直流电disconnect 切断electronic control 电子控制fuse 保险丝fuse box 保险丝箱distribution panel "distro" 配电箱ground (US)/earth (UK) 接地;地线grounded (elec.) 已接地线impedance 扼流线圈〔阻抗〕increase (to) 增大;增加input voltage 输入电压lead (UK)/cable/leg 电缆load (elec.) 负担main circuit 主电路neutral (elec.) 不带电的ohm 欧姆(电阻单位outlet (elec.) 插座output voltage 输出电压overload (elec.)"pop the breaker" 超载phase (elec.) 阶段power (elec.) (W) 电力primary current 主要电流AC to DC adapter(rectifier) 整流器reduce (to)"breakdown to" or "kill"(off) 减少kill(off) 关闭secondary current 次电流short circuit/shorted out/burned up 短路strap 束住turn off (to)/kill 关掉/切turn on (to)/bring dim to 使硅箱数字到Dip in intensity 亮度暗下voltage 伏特数tie line 绑住绳wattage 功率cables 电缆Twofers(pigtail) 二合一电缆Threefers(Martingale) 三合一电缆Wire Gauge 线材号数Adapter (Cable) 适配器(电缆)Cable 电缆Connect (To) 连接〔向〕Control Cable 控制电缆Extension Cable/Cord 延长线Feeder Cable feeder,ought(4-0)cable,(3-0)cable Optical fibers 光学纤维cable loom - hooded together, multiConnectors 电接线器plug 插头(男性)receptacle/socket(female) 插座(女性)new style twist lock 美国舞台插座old style twist lock 美国舞台插座stage pin 美国舞台常见插座Edison 美国家庭插座dips (UK) (elec.)/floor pocket (US) 英国舞台常见插座drop box 地面插座floor pocket 地板袋wall pocket 墙壁袋Camlock camlock3pin DMX XLR数据缆4 pin 彩色卷轴使用数据缆5pin dmx cable dmx 数据缆accessories 配件fan (elec.) 风扇ghost light 当剧院不在使用时用的灯remote control "r-fu(arfoo)" 远程控制器resistance device 阻器件transformer (elec) 变压器ballast 照明设备用镇流器Tools 工具wire stripper 电线剥离器tie wrap 可能关闭的线条Allen key 特别适合扳手crescent wrench 月牙扳手gaffer tape 不会留下痕迹磁带electrical tape 电子磁带pliers 钳子scissors 剪刀insulating tape 隔热胶带tape measure 卷尺Hanging position 悬挂位置truss 桁架grid 网格box boom 包厢杆Front of House electric 前台灯杆Cove 洞穴ceiling beam 天排ground row 地排boom 灯架trim 整理好的高度light tree 灯光柱light slot 灯光槽first electric 一顶排second electric 二顶排stage electric 舞台上边的电杆Juliet 台口灯架gallery/bridge 桥Balcony Rail 挑台杆tower 柱ladder 吊笼movable boom/tower"rovers" 可移动灯架/流动灯架aisle 走道Arm 臂method of hanging 悬挂方法bank of lights 一堆灯daisy chain 菊花链double hang(truss) 双〔桁架〕吊灯gang together 连接一起hook up 接电yoked out 面对外界underhang 吊柱下面挂Lighting Directions 灯光灯位lighting key 根本的灯光front light 面光low side light 柱光back light 逆光general wash 根本照明highside 桥光kickers 耳光top light 顶光cyc lights (top row) 天排cyc lights (ground row) 地排foot light 脚光accent 强调,dead spot 不能被点亮的地方special pool 特殊灯具Instrument "零件"Parts 镜片aperture 孔径plano convex 平突透镜片concave lens 凹透镜片shuttercolor scroller 彩色卷轴lens 镜片base 座子lens tube/barrel 镜片管/桶lens holder 镜片lens hood 突出lens lamp 灯泡lighting capacity 照明能力diffusion lens 滤色镜light distribution 光分布light source 光源parabolic beam projector 抛物线束投影parabolic reflector 反光碗safety light 平安灯Field Angle 聚光角度beam angle 散开角度Roundale 圆突出镜片fresnel lens 聚光突出Lamps 灯泡HMI 鏑燈tungsten 照射器halogen 钨LED 卤素filament 灯丝fixed focused 固定装置使灯泡incandescent lamp 白炽灯Convectional Lights 普光灯具Lens Spotlight 平凸透镜聚光灯Fresnel Spotlight 螺纹聚光灯Beam Projector 回光灯Flood Light 泛光灯PAR Light PAR灯,帕灯Variable Focal Length ERS 成像灯Ellipsoidal Reflector Spotlight 椭球反射灯Source 4 ERS 成像灯Effect Projector 效果灯Moving Lighting 电脑灯black lights 紫外线灯discharge lamp 发射灯xenon lamp 氙气灯Accessories 配件barndoor 遮光屏遮shutter 切割片gel 颜色片mirror 镜子motor 马达dip switch DIP篇组开关Gobo / Template 图案片shutter 造型片color frame 色片框iris 光阑top hat 礼帽funnel 烟囱Black Foil 黑色金属片Intensity Control 亮度控制lumen 流明footcandle 根本烛光Lighting munication 灯光控制系统DMX 512 数字系统AMX 192 模拟系统ethernet 太网Architecture for Control Network(A) 构造的控制网络mon shield 共同盾data plement 相反数据data true 正数据termination 末端terminator 末端电阴start/base address 起始地址编码unidirectional 只有单方向dmx splitter dmx别离机Device Description Language (DDL) 设备描述语言input/output ports 输入/输出端口system bus 系统线DMX data packet dmx数据包Idle 没有数据break 数据包开场标记Mark after break(MAB) 开场标记后第一个标记start(SC) 开场代码mark time between frame(MTBF) 通道数据开场/完毕channel data(CD) 通道数据Mark Time Between Packet(MTBF) 数据包完毕标记Dimmers/patch bay 硅箱器/配接台dimmer rack 硅箱架SCRIGBTdimmer cabinet 硅箱柜dimmer number 硅箱数字dimmer per circuit 硅箱数字等同控制通道non-dim 零开关hard patch 用连接电缆交接lighting Console 电脑灯光控制台channel 控制通道crossfader 穿插变光Group 编组功能Script file programming 编辑手写文档Clear 按钮去除当前的光路输出memory 记忆场景按钮menu 菜单区PROGRAM 编辑模式SUPERVISOR 管理模式SAVE OUTPUT SCENE 记忆场景键ENVIRONMENT 环境chase 场景跑灯Scene 场景auto follow cue, "wait cue" 自动跟随的灯光变化Highest takes precedence 最大优先Latest takes precedence 最后优先soft patch 使用软件接线cue 灯光变化(Q)Channel Control Mode 控制通道模式Monitor 显示器master console 主控制台slave console 众控制台Operation keypad featuresGrand master 根本控View 查看enter/* 确认clear/rel 释放/去除submaster 集控unfold 展开page 页save 保存sliders 手推控wheel 手轮swop 替换add 添加reset 回到过去preset 预置playback 重放active 活性的Display Keys 橱窗Stage/live 舞台上即显示Blind/preview 舞台上不显示/预览Setup 设定patch 接线Navigation Keys 导航up arrow/page up 向上箭头/上一页down arrow/page down 向下箭头/下一页last screen(Space Bar) 最后屏幕〔空格键〕cues recording 灯光变化记录record/rec 记录time/rec 时间enter/* 输入/ *up time 上的时间down time 下的时间fade in/out 光上/下flash 闪存solo 单独Numeric Keysand 并且at/ 于attrib 特点channel 输出通道cue 灯光变化dim/dimmer 硅箱数字except 除了focus 聚焦full 最亮hold 持有last 上个level 亮度linknext 下一个off 远的on 安大概page/sub page 页/集控分页record 记录rel/clr 释放/去除rem dim 下一个shift 转移sub 页thru 直到time 变化时间track/cue only 跟踪/不跟踪灯光变化(Q) type/profile(?) 类型undo 撤消update 更新user 用户wait 等待cue running 灯光变化(Q)go/goto 走动hold 持有text 文字profile 总那么pb 铅macro 宏load 加载cut 切割stop back 停顿返回rate 比率stop 停顿SoftKeys(features) 执行灯光变化(Q) dimmer double 一硅箱数两输出通道previous page 前一页next page 下一页unpatch 别离交接patch 交接add channel 添加输出通道effect 效果delete cue 删除灯光变化single scene preset 单一场景预置submaster pages 集控页submaster bump 集控park a channel 固定输出通道exclusive 独立的group 组For Moving Light 电脑灯colormix 混合色DowserFlash 灯具点控Fixture 按钮palette 调色板Color Field 颜色选配pan 水平移动tilt 俯仰移动frost 雾化功能pan fine 水平微调tilt fine 俯仰微调Pan Angle 最大垂直角度〔以度数为单位Tilt Angle 最大角度〔以度数为单位P/T_Speed 移动速度zoom 可变焦focus 聚焦gobo 图案片sharper rot 成像转动90度STROBE 阻断闪动COLOR1 CORR 色温校正PRISMA1 柔光棱镜Gobo rotator 图案轮一旋转CONTROL 灯炮控制+HP/HNCPU 中心处理机Memory 存储Color Picker 拾色器munication 通讯shadow 阴影Swop 交换按钮take over 切换Iris 可变光阑Lighting image/Color 照明图像/颜色Image 照明图像beam 散开hard 聚光soft 柔光diffused 分散split(leak) 漏光Silhouette 剪影Color 照明/颜色gold 金amber 琥珀色straw 黄褐色indigo 靛蓝lavender 淡紫色Infrared 靛蓝色Ultra Violet 紫外线Cie Color System 国际照明委员会色度图Characteristic 特征Color Harmonies 颜色和谐Color Perspective 彩色透视Digital And Electronic Color 数字化和电子颜色Kevin degree 色温度量Primary Color 三基色Reflection 反射Simultaneous Contrast 同时比照Color Spectrum 色谱Subtractive Color Mixing 减少色光Additive Color Mixing 添加色光Cold Color 冷色Transparency 透明度Color Temperature 色温Chroma(Saturation) 饱和度Chromatic Aberration 色象差wavelength 波长Value 亮度Warm Color 暖色plementary Color 互补色Hue 色泽Special effect 特殊效果pyrotechnic technique 烟火技术projection 投影slide projector 幻灯投影机slide 幻灯片snow bag 雪袋illusion 假象light curtain 光帘lighting battle 灯光战斗Accessories 配件Color Filters 色纸Color Gel 色纸Color Wheel 色轮Color Meters 色平盘算表战斗Paperwork 文件/繪圖stencil 模版craft paper 牛皮纸Light 燈光Light Plot 燈光設計圖hook up chart 电缆连接图Instrumental Notation 燈具符号Legend 说明;图例Light Archive Plot 存媒體內的執行提示表列印稿Light Equipment List 燈具Light Plot (Section) 燈剖面圖Lighting Dimmer/Channel Schedule 电缆连接图Lighting Electrician's Cue Sheet/cut list 燈光提示表Lighting Instrument Schedule 燈具配置表Lighting Magic Sheet 燈光快速檢索示意圖lighting inventory 燈光存货lighting rendering picture 燈光效果图Title Block 标题costume 服装costume chart 服装图costume list 服装costume calendar 服装日历Building 剧场建立seating plan 座位表Architectural Drawings 建筑图表Scenery 布景hanging plot 吊景图解line plot 吊杆图解Line Drawings 吊杆图解fly schedule 吊杆操作表shift plot 布景搬移Property 道具Property Plot 道具图解property inventory 道具存货Sound 音響Sound plot 音響图解equipment list 音響Stage Management production schedule 制造日程表prompt Script 提词用剧本route sheet 路线图cue list 提示表Cast list 演员script 剧本block diagram 根本的草图ViewSection 剖面圖top 平面图isometric 三维等距back 反面圖panorama 全景Scenery 布景Scenic Production Team 布景制作队Scenic Designer 布景设计师master carpenter 主要木匠scene foreman 布景领班carpenter 木匠painter 漆匠draftsman 草案Tools 工具Wood Tools 木工工具Measuring Tool 量具Tape Measure 卷尺Tri Square 三坊bination Square 组合曲尺Bevel Protector 锥保护Framing Square 丁字尺Carpenter's Level 水平尺folding rule 折叠规那么steel tape 钢卷尺卷尺measure gauge 衡量指标centering square 中心正方形spring curve/spine 曲线/样条Marking Tool 标记工具pencil 铅笔scribe 文士chalk line 粉笔线chalk 粉笔charcoal 炭笔Hammers 锤claw hammers 爪锤ball peen hammer 球喷丸锤mechanic's hammer 机械师锤tack hammer 钉锤mallet hammer 锤锤planer 刨床block plane 短刨smoothing plane 光滑刨files 锉wood rasp 木粗锉wood file 木锉metal file 铁锉Cutting Tools 切削刀具saws 锯crosscut saw 横切锯rip saw 锯backsaw and miter box 轴锯箱keyhole saw 锁孔锯coping saw 应对锯hacksaw 钢锯utility knife 美工刀portable circular saw 便携式圆锯saber saw 马刀锯table saw 桌锯jigsaw 拼图锯band saw 带锯radial arm saw 辐射臂锯handheld power saw 手持式电动的锯fixed power saw 固定电源看见bolt cutter 螺栓切割机Scissors 剪刀tin snips 锡snipswood chisel 木凿子cold chisel 冷凿drilling tools 钻井工具hand drill 手钻brace 支撑push drill 手推钻power drill 电力手钻drill press 钻床手钻electric hand drill 电动手钻heavy duty hand drill 重型手钻cordless drill 无绳演习Bits 钻头twist drill bits 头wood bits 木材钻头push drill bits 手推钻头hole saws 孔锯Clamping Tools 夹紧工具carpenter's vise 木匠老虎夹machinist's vise 机械师的老虎夹adjustable wood clamp 可调木夹belt clamp 带夹子pipe clamp 管夹C-clamp C-夹spring clamp 弹簧夹quick clamp 快速夹夹hand screw clamp 螺丝夹brace cleat 支撑理夹Pliers 钳子slip joint pliers 滑联合钳子long nose pliers 长鼻子钳子adjustable arc-joint pliers 可调弧形联合钳子locking pliers 锁钳子diagonal cutters 斜切割机wire crimping tool 电线卷曲工具Wrenches 扳手open-end wrench 开放式扳手box end wrench 方块扳手adjustable-end wrench 可调整的扳手crescent wrench 月牙扳手socket wrench 套筒扳头screwdrivers 螺丝刀standard screwdriver 标准螺丝刀Phillips screwdriver 菲利普斯螺丝刀nut driver 螺母司机ratchet screwdriver 棘轮螺丝刀miscellaneous 杂项wire strippers 电线脱刀sandpaper 砂纸wrecking bars 抢险酒吧nail puller 拉钉扳手grommet set 金属扣眼设置oil stone 石油石staple gun 订书机gimp tacks 绒丝带针gimp tapes 绒丝带胶布Air Tools 空气工具air line supply 空气供给线pressor 压缩机pneumatic wrench 气动扳手pneumatic nailer 气动拉钉spray gun 喷枪Metal Tools 五金工具metalworking Hand Tools 金工手开工具anvil 铁砧conduit bender 管道弯管center punch 中心冲割机bolt cutter 螺栓切割机pipe cutter 管道切割机tap and dies 水龙头和模具marking tool 标记工具scribe 抄写工具china marker 瓷器标记pass 指南针inside caliper 卡尺vernier caliper 游标卡尺centering square 中心丁字尺metal straight edge 金属直边Shaping Tool 整形工具leaf foams 叶泡沫saddle-shaped sill iron 马鞍形窗台铁bracket 支架wagon guide 指南车nipper 钳Cutting Tool 切削刀具hacksaw 钢锯abrasive wheel saw 砂轮锯hand hacksaw 手钢锯metal cutting blade in scroll saw 金属切削刀片的滚动看见side cutter 侧铣刀end cutting nippers 完毕切割钳tin shears 锡剪power band saw 电力锯power sheaer 电力剪power nibble 电力轻剪Soldering 焊接propane torch 丙烷火炬soldering iron 烙铁soldering gun 焊锡枪Welding Equipment 焊接设备gas welding equipment 气体焊接设备arc welding equipment 弧焊设备gas metal arc welding 气体金属弧焊oxygen tank 氧气筒acetylene tank 乙炔罐tank truck 油罐车gauges: oxygen regulator 压力表：氧气调节器hose 软管welding butt 焊接对接cutting attachment 切割附件welding nozzle 焊接喷嘴tip cleaner set 提示清洁设置flint lighter 砂轮打火机welding gloves 焊接手套goggles 护目镜brazing rod 钎杆folding screen 屏风wire feeder 送丝机helmet 头盔Miscellaneous Power Tools 杂项电开工具router 路由器wood lathe 木车床bench sander 替补桑德bench grinder 砂轮机Paint Shop 油漆工作室dry paint 干漆ready mix paint 准备混合涂料scenic paint 风景涂料solvent 溶剂pigment 色素dyes 染料flame proofing 火焰防护enamel/lacquer 光漆glaze 上光漆gouache 水粉画sealant 密封膠flammable paint 易燃漆Process 条理,方法base coat 根本层prime coat 打底lining 里层texturing 纹理stenciling 制版pouncing 冲击sawdust coat 木屑层water putty 水腻子joint pound 联合混合物marble coat 石层tenon 榫头Method of Painting 油漆方法horizontal painting 横向绘画stationary frame 静止画面spatter 喷溅Painting Tools 油漆工具primary brush 主要刷decorating brush 装饰刷bevel brush 启动刷Painting Tools 油漆工具paint frame 油漆框架moving frame 移动框架elevating frame 提升框架beveled straightedge 斜角直尺rule or steel tape 规那么或钢卷卷带snap line 单元线bow snap 弓单元plumb bob 铅垂线charcoal stick 炭棒画笔large pass 大规围tank sprays 坦克喷雾剂spray gun and pressor 喷枪及压缩机pounce wheel 猛扑轮buckets 水桶small pots or cans 小壶或罐burner and double boiler 锅炉和双燃烧器flogger 抽打paint roller 油漆滚轴furnitureworkbench 工作台Scenery Material 布景材料drapery 布料Irish Linen 爱尔兰亚麻canvas 油画muslin/gauze/shear 细布/纱幕scrim 平纹棉麻burlap 粗麻布wallpaper 壁纸fireproof curtain 防火幕canvas 帆布Styrofoam 发泡胶Scenery Parts 布景零件air caster 空气脚轮backing flat 支持片batten (wood) 木box set 盒子布景brace/jack (adjustable) 支撑/斤顶〔可调〕brace/jack (fixed) 支撑/斤顶〔固定〕brake 制动castor 小脚轮castors, swivel 脚轮，转动castors: fixed 脚轮：固定castors: lifting 脚轮：取消castors: with brake 脚轮：刹车ceiling 天花板column 柱beam/crossbar 横梁flippers 蛙鞋floor 地面floor tape 地面磁带foot iron 铁桎frame (rostrum) 框架〔讲台〕framed (scenery) 框架〔布景〕gap in the masking 差距在掩蔽gauge (thickness) 衡量〔厚度〕ground row (scenery) 地面排〔布景〕hand rail 扶手hanger iron 铁衣架hanging piece 挂片lash line 绑扎线lift jack 升降机斤顶masking 掩蔽monofilament 单线outrigger 支腿railing 栏杆roller bracket 辊支架set 放置组合side masking 侧面掩蔽stair landing 楼梯着陆stairs 楼梯toggle rail 切换铁路tread (stairs) 胎面〔楼梯〕wall bracket 墙壁支架Part of a Flat 布景片stile 垂直支架keystone 连接rail 横支架toggle 中支架corner block 拐角片diagonal brace 斜撑stiffener 补强板jack braces 独立三角支架set piecesfoliage border 树叶边界carpet 地毯door 门door frame 门框pillar 支柱platform 平台drop 幕drop: cut 幕：切削drop: framed 幕：框架window 窗口MethodDutchman 修补float 浮动flown 飞上/下overlapping 重叠hang 附著/吊change (to) 变化〔至〕change over time/turn around time 随着时间推移而改变/扭转时间changeover (scenic, lights) 转换〔风景，灯光〕waterproof 防水sizing 浆纱收缩fire retardant 阻燃Scene Change 布景变化Quick Change 快速变化shift 搬移paper 文件running order 运行序obvious change 明显变化convertible set 可兑换的布景set change 布景变动running time, playing time 运行时间，上场时间multiple setting 多个布景demountable set 可拆卸布景box set 匣子布景temporary set 临时设置permanent set 常设设置portable set 便携式布景coloropaque 不透明transparent 透明translucent 半透明Management 管理On Stage 舞台process 進程audition 面試blocking 走位character analysis 個性分析script analysis 研读剧本dress rehearsal 彩排dry run 没有光或声音的彩排dry technical 干技术彩排light check 檢查光light rehearsal 光的彩排paper tech 紙上彩排preview 預覽Production Meetings 製作会议QtoQ/CueToCue 只是提示的彩排stage rehearsal 舞台上彩排strike 卸台technical rehearsal 合成彩排load in/load out 装台/卸台run through 刚是要点彩排Performing 在表演中entrances 演员进入舞台exits 演员离开舞台curtain call 幕Intermission 休息prologue 序幕coda 尾声episode 情节中的插曲applause 掌声finale 最后一幕Encore! 再来一次Personnel 员工Stage Manager 舞台监视Assistant Stage Manager 辅助舞台监视Stage Crew 舞台工作人员gopher 跑腿Notice Board 公告板call board 通告板sign-in sheet 到达表panic switch 应急开关Contact Sheet 联络表prompt board 提示板prompt desk 提示台Types of Cues 提示sight(visual) cue (视觉)提示cue light 用灯作提示变化sound cue 声音变化entrance cue 用入口定提示carpenter's cue 吊杆变化shift cue 换景变化standby/warning 准备提示Paperwork 文书工作Performance Log 表演日誌call sheet 到达时间日程表schedule 日程表schematic representation 示意圖prop list 道具列表blocking notation 走位記法Check list 清单shift plot 换场，换景計劃strike plan 收場計劃synopsis 剧情简介cue list 变化表fly schedule 吊杆操作表Necessities 必需品First Aid Kit 急救藥箱whistle 哨子warning light 警示燈Front of House Management 礼堂管理house manager 经理usher 引座员late arrival 迟到的观众box office 门票部advance booking 預訂children ticket 兒童票p 赠票door count 进入人計數full price 全價half price 半價reservation 定座returnable ticket 可退門票rush seat 匆忙座位seating chart 座位圖seating plan 座位表senior discount 老人折扣sold out 全部售光student ticket 學生票ticket agency 售票代理ticket broker 售票經紀equipment/practiceexchange courtesy 禮貌互換early door 早進入观众座air conditioning 空調warning bell 提示鈴house open 可以進入观众座half hour call 给予演员半小时前开演的通知quarter hour call 给予演员15分钟前开演的通知Theater BuildingArchitectural StyleOpen Air Theater 露天剧场Thrust 伸出式proscenium 镜框式舞台Arena - theater in the round 环型剧场amphitheater 半露天剧场Black box 实验剧场/黑盒子的舞台promenade theater 长廊剧场pavilion 大帐篷platform stage 开放式舞台coliseum 体育馆hippodrome 赛马场peep-hole stageBackstage 后台Dressing Rooms 更衣室wardrobe rack 衣柜架dummy 假人模式wardrobe crate 衣柜箱Laundry Room 洗衣房washing machine 洗衣机drying machine 干衣机iron 熨斗ironing table 熨衣板dry cleaning 干洗。
输电线路杆塔空气间隙三维可视化管理系统
输电线路杆塔空气间隙三维可视化管理系统许焱1，郭宁1，张辉1，苗堃1，李超1，刘亚文2*（1.国网河南省电力公司济源供电公司，河南济源459000；2.武汉大学遥感信息工程学院，湖北武汉430079）摘要：在Web GIS 框架下构建了真三维场景的防风偏参数杆塔空气间隙管理系统，提出了兼顾数据量和表现力的无人机摄影测量输电线路建模方案，保证了三维场景的精细度与可量测性，并设计了合理的系统多源数据组织方式及数据浏览、查询、分析等功能。
实践表明，该系统能够实现在真实三维场景下，对杆塔空气间隙的查看、浏览与分析，为输电线路防风偏提供有效的分析平台。
关键词：杆塔空气间隙；可视化管理系统；输电线路点云模型中图分类号：P208文献标志码：B文章编号：1672-4623（2022）04-0163-05doi:10.3969/j.issn.1672-4623.2022.04.035Transmission Line Tower-line Air Gap Management SystemBased on 3D Visualization SceneXU Yan 1,GUO Ning 1,ZHANG Hui 1,MIAO Kun 1,LI Chao 1,LIU Yawen 2(1.State Grid Henan Jiyuan Electric Power Supply Company,Jiyuan 459000,China;2.School of Remote Sensingand Information Engineering,Wuhan University,Wuhan 430079,China)Abstract:The tower-line air gap management system with real 3D scene based on Web GIS was constructed.This paper presented a transmis-sion line modeling scheme on UA V photogrammetry that ensures 3D scene precision and measurability.A reasonable multi-source data organiza-tion and data browsing,query and analysis functions were designed for this management system.The practice shows that this management sys-tem can achieve tower-line air gap query,browse and analysis in real 3D scene,and provide a reliable analysis platform for transmission line windage yaw prevention.Key words:tower-line air gap,management system on 3D visualization scene,transmission line point model随着通信技术、网络技术的广泛应用，结合Web GIS 和虚拟建模技术的输电线路管理系统成为主流，如文献[1]将三维仿真场景同日常输电线路管理结合起来，实现电网企业智能化的运行和管理。
最全的压铸模具相关英语注释
超值压铸英语A 安装尺寸install dimension凹模固定板retainer plate凹模female die, female mold，negative moldB 备件spare parts变质modification变质剂modification agent扒渣slagging—off保温炉holding furnace保压压力dwell pressure表面缺陷surface defectC 淬火硬度quenching hardness抽芯core侧面抽芯side core抽芯油缸core oil cylinder插拔式结构plug抽芯机构core puller抽芯油缸支架bracket of cylinder粗糙度roughness/degree 铸件表面粗糙度surface roughness擦伤galling尺寸公差dimension tolerance of casting除气degassing吹气净化blow purifying除气剂degassing flux出渣de-slagging出渣口slag hole沉渣sludge出炉口tap hole菜花头Cauli—flowering超声波检验ultrasonic test重熔re—meltingD 端盖cover动模垫块spacer parallel锻钢forged steel氮化处理nitriding treatment断裂fracture塑性断裂plastic fracture导柱guide pillar导套guide sleeve导向板guide plate导向件guide part动型moving die/ejector die/movable mould动模座板moving clamp plate/bottom clamping plate 定模座板fixed clamp plate/top plate定型fixed die/cover die定模套版bolster/fixed die顶杆ejector pin顶出结构ejector mechanism顶出ejector吊装孔lifting eye吊环lifting ring镀钛处理titanium plating treatment多肉缺陷metallic projection电火花electric spark打磨grindingF 分流锥divider/blast cone分型面mold parting/parting face/mold joint附页attachment/appendix复位杆reset bar(rod)附件故障accessory覆盖剂covering flux废金属料scrap浮渣cinder反射炉reverberatory furnace废品reject飞边joint flash仿真simulationG 规格specification/standard 数值孔径numerical aperture (N。
3D geometric modelling based on NURBS_ a review
3D geometric modelling based on NURBS:a reviewE.Dimas a,b,*,D.Briassoulis ba Catholic University of Leuven,Leuven,Belgiumb Agricultural University of Athens,Agricultural Engineering Department,75Iera Odos Strasse,11855Athens,GreeceReceived8November1996;accepted2October1998AbstractThis article reviews the prevailing geometric modelling techniques,based on Non-Uniform Rational B-Splines(NURBS).Emphasis is placed on the most important properties of NURBS surfaces and the available techniques for modelling real natural or artificial objects given a cloud of three-dimensional data points on their surface,possibly taken from a scanning device.᭧1999Elsevier Science Ltd and Civil-Comp Ltd.All rights reserved.Keywords:Non-Uniform Rational B-Splines;Be´zier curves;B-Spline curve1.IntroductionGeometric modelling has already become an important tool for a variety of applications in manyfields such as industrial design and manufacture,electrical and mechan-ical engineering,biomedicine,etc.Design and manufacture of such diverse objects such as aircraft,cars,ship hulls, shoes and bottles harvest the benefits of the emerging tech-nology and simultaneous intensive research in the mathe-matical theory,representation and analysis of surfaces.As a result,physical objects have widely been replaced by computer models.This leads to better and cheaper products as the latter are simpler to analyse and easier to change than the former.The aim of this article is to provide a survey of Non-Uniform Rational B-Splines(NURBS)surface properties and available modelling techniques.In the remaining section,we present different existing modelling principles and their underlying mathematical representations.We also give a historical summary of the development of NURBS curves and surfaces.In Section2,we present some of the basic properties of univariate and bivariate rational basis functions.In Section3,we define NURBS surfaces and present their most important properties.Section4gives the NURBS characteristics of commonly used surfaces. Section5presents some free-form surface modelling tech-niques based on NURBS when the input data is a cloud of three-dimensional(3D)points.We conclude in Section6 with topics of future research developments.1.1.Modelling philosophies and underlying mathematical representationsGeometric modellers can differ in the mathematical representation scheme of geometric entities.An important distinction of this kind is between implicit and parametric representations.It is only a natural consequence that algo-rithms are heavily influenced by the choice of modelling philosophy and mathematical representations.A parametric surface takes the formx s;t x s;t ;y s;t ;z s;t T; 1 hence,it is essentially a mapping of a domain DʚR2to R3. In an analogous manner,a parametric curve is a mapping of DʚR to R2or R3.Be´zier,B-Splines,NURBS curves and surfaces are the most popular of parametric representations. NURBS curves represent a natural generalisation of B-Spline and Be´zier curves.Bivariate NURBS surfaces are the proper generalisation of tensor product B-Spline and Be´zier surfaces.Implicit surfaces are defined as the zero contour of a scalar-valued function,i.e.they are sets of points[x,y,z]T which satisfyf x;y;z 0: 2 Implicit curves are defined as the intersection of two implicit surfaces,i.e.their defining equations aref1 x;y;z f2 x;y;z 0: 3Advances in Engineering Software30(1999)741–751 0965-9978/99/$-see front matter᭧1999Elsevier Science Ltd and Civil-Comp Ltd.All rights reserved. PII:S0965-9978(98)/locate/advengsoft*Corresponding author.E-mail addresses:lcon4div@auadec.aua.gr(E.Dimas),Briassou@ auadec.aua.gr(D.Briassoulis)Sometimes other representations can be used(for exam-ple explicit representations),but parametrics and implicits are predominant in the academic,industrial and commercial world.Geometric modelling systems can also differ in“philoso-phy”.Historically,there have been three–different in prin-ciple–kinds of geometric modelling systems,used in industrial applications:wireframe,surface and solid model-lers.Thefirst and simplest models,created with the aid of computers were wireframes.Straight lines,conics or simple spline curves are used to represent the boundaries of the object to be modelled.However,lack of explicit surface information can lead to models which are ambiguous, incomplete or even impossible to manufacture as they can correspond to no physical3D object[1].These drawbacks led to the search of more sophisticated schemes.Conse-quently,wireframe systems gave way to surface and solid modellers.Surfaces are used explicitly to describe an object in surface modellers.More complex shapes can be modelled with surface modelling than with wireframes.By definition,a solid is a3D object with a well defined inside and outside separated by a two-dimensional(2D) boundary.Many techniques have been developed for gener-ating and storing geometric models which are represented as solids,such as Constructive Solid Geometry(CSG),Bound-ary representation(B-rep),octrees and others[2];thefirst two being the most popular.For more details on the devel-opment of solid modelling systems,see[3,4].For a recent survey on strengths and limitations of solid modelling systems,see[5].Early solid modelling systems incorporated planar and quadric halfspaces(sphere,cylinder,etc).However,design needs are far greater.There is much ongoing research on algebraic free-form surface design now[6–10],the inclu-sion of free-form surfaces(either in algebraic or parametric form)in solid modellers[11],and the evolution of parallel processing algorithms[12].From the point of view of the techniques used for geometric modelling purposes,there are two basic approaches:transfinite interpolation and discrete approxi-mation and interpolation.In transfinite interpolation,a surface is constructed such that it goes through a given collection of curves.Cross-sectional design is an example of a method that falls into this category[13].In discrete approximation(interpolation),a surface that approximates (interpolates)a given set of data points is constructed. Based on the manner in which a change in the data affects the curve or surface to be constructed,we can categorise methods into global and local.In global methods,a change in the data affects the whole surface while in local methods such a change affects the surface locally.In thefirst category are methods like the Gordon surface[14]and polynomial Be´zier surfaces.However,if there are a lot of data the degree of the polynomial surface required tofit the data is high,which makes the resulting surface unreasonably complicated for further manipulations.Therefore,designers are more interested in local methods in which a change in the data affects the curve or surface locally(in regions in the vicinity of the data change).Local methods invoke piece-wise triangular polynomials or bipolynomials to define the desired surface.Such techniques include piecewise Be´zier, B-Splines,Rational B-Splines and NURBS curves and surfaces.Usually,there is an initial polygonal or polyhedral approximation of the desired object given in terms of a triangulation[15]or a rectangular grid of control points. The initial polygon or polyhedron is then smoothed using triangular or rectangular(tensor product)piecewise smooth patches.For piecewise Be´zier,one has to enforce smooth-ness conditions between adjacent patches[17–19],but with the B-Spline or NURBS scheme,this comes without any special tricks.A drawback of rectangular patches is their limited ability to model complex topologies.Very often there are n-sided (n 4)holes within a rectangular patch complex.Techni-ques forfilling such holes with smooth triangular or rectan-gular patches have been reported earlier[16].However, such problems are avoided using triangular patches,as more complex topologies can be modelled with triangles rather than with rectangles.However,triangular or rectan-gular patches are not the only ones available for modelling purposes.There have also been n-sided(n 3,4)patches and smoothing techniques based on them reported in the literature[20–24].1.2.HistoryBe´zier curvesThese were independently developed by Be´zier at the Renault car company in1962and De Casteljau at Citroen in1959.As Be´zier’s work became known earlier,Be´zier curves are known by his name.B-Spline curvesThey are the proper generalisation of Be´zier curves.They were initiated by De Boor[25],but were concerned with approximation theory aspects.It was Gordon and Riesenfeld [26]that married the theory of B-splines with that of Be´zier curves.Rational curvesThese were considered by Coons[27].Forrest pursued the ideas further,particularly in connection with conics and cubics.Following Riesenfeld,Vesprille[28]wrote the first report on NURBS in1975.See also[29,30].Tensor product Be´zier surfacesThey started developing in the late sixties,although De Casteljau and Ferguson started experimenting sooner.For tensor product B-Spline and NURBS surfaces techniques see[31–38].Triangular Be´zier patchesThey werefirst considered by De Casteljau.In theirE.Dimas,D.Briassoulis/Advances in Engineering Software30(1999)741–751 742Lagrangian form,they are widely used infinite element methods.They have been extensively studied by Farin[39]. B-Splines over trianglesThey werefirst considered by Sabin.Triangular B-Splines surfaces have been studied in[29,36,40–43].For a survey of modelling methods in CAGD,NURBS design techniques,and a classification of some smoothing techniques,see[44],[45]and[46],respectively.2.B-Spline and NURBS basis functionsThis section presents the definition and most important properties of univariate and bivariate B-Spline and NURBS basis functions.2.1.B-Spline basis functionsLet U {u0;u1;…;u i;u iϩ1;…;u m}be a non-decreasing sequence of real numbers(U is called a knot vector).Then, the following expression defines the i th normalised B-Spline function of degree p recursively.N p i uuϪu iu iϩpϪu iN pϪ1iu ϩu iϩpϩ1Ϫuu iϩpϩ1Ϫu iϩ1N pϪ1iϩ1u ; 4whereN0i u1;if u iՅuՅu iϩ1;0;otherwise:@5The interval u i;u iϩ1 is called the i th knot span.A knot vector is non-periodic if thefirst and last knots are repeated with multiplicity pϩ1,i.e.U {u0;…;u0;u pϩ1;…;u mϪpϪ1;u m;…;u m}.For most practical applications,u0 0and u m 1.Knots u pϩ1;…;u mϪpϪ1 are called interior.Further,a knot vector is called uniform if the knots are equally spaced,i.e.there exists a positive real number h such that u iϩ1Ϫu i h,pՅiՅmϪpϪ1. Otherwise,the knot vector is non-uniform.Non-uniform knot vectors offer greaterflexibility for various design appli-cations[32,47,48].B-Spline functions are a natural generalisation of Be´zier functionsB p i upi23u i 1Ϫu pϪi 6for the knot vector with no interior knots,i.e. U {0;…;0;1;…;1},where the0s and the1s are repeated pϩ1times.2.2.NURBS basis functionsWe can now define the NURBS basis functionsR p i uw i N p i unj 0w j N p j u; 7where w i are nϩ1( mϪp)positive real weights.Also note that if all weights are equal,i.e.w i w,for i 1,…,n, the rational basis functions degenerate to B-Spline basis functions(see partition of unity property).Therefore,they are generalisations of B-Splines.Indeed,R p i uN p i u if w i w;i 1;…;nB p i u if w i w;i 1;...;n;U {0;...;0;1; (1); @8 where the0s and the1s in U are repeated pϩ1times.Fig.1 gives an example of a cubic NURBS basis function.In the following,we will drop the superscript p indicating the degree of the basis functions when it is not necessary for clarity or it is evident from the context.The properties of R i are inherited from the normalised B-Spline functions.In particular,we have•Non-negativity:R i(u)Ն0.•Partition of unity:ni 0R p i u 1.•Non-negativity and partition of unity means that0ՅR i(u)Յ1.•Local support:For u [u i,u iϩpϩ1],R i(u) 0.In other words,R i(u)is“active”(non-zero)only in the interva-l[u i,u iϩpϩ1],i.e.from knot u i and forward.•In addition,in a knot span u iϪ1;u i ,the only non-zero basis functions are R j(u),iϪpϪ1ՅjՅiϪ1.This is an on–off switch effect,as in the next interval u i;u iϩ1 , R iϪpϪ1(u)becomes zero and R i(u)becomes active(non-zero).•Differentiability:If the multiplicity of a knot is k,then the basis function is pϪk times continuously differentiable at this knot.It is infinitely continuously differentiable in the interior of a knot span.•For pϾ0,R i(u)has exactly one maximum value in u i;u iϩpϩ1 (where it is non-zero).E.Dimas,D.Briassoulis/Advances in Engineering Software30(1999)741–751743Fig.1.Cubic NURBS basis functions,with knot vector U {0,0,0,0,1/3,1/ 2,1,1,1,1}and weights w {1,0.3,0.5,1.5,0.3,2}.•With regard to the influence of weights on the shape ofthe basis functions,the following can be easily proved •For w i 0,R i (u ) 0.•For w j 3∞,R i (u )31,if j i and R i (u )30,if j i .Fig.2shows the influence of a change in the weight w 3on the cubic basis function R 3of Fig.1for w 3ʦ[0,5](all other weights are kept fixed).In general,for u ʦ(u 0,u m )when w i increases,R i (u )increases and R j i (u )decreases.2.3.Bivariate NURBS basis functionsFor reasons which will become apparent in the next section,in order to define rational B-Spline surfaces we use rational B-Splines basis functions of degree (p ,q )R p ;q i ;j u ;vw ij N p i u N q j vk r 0 n s 0w rs N p r u N qs v : 9Naturally,two knot vectors U ,V associated with N p i u and N q i v ,respectively,are now required.The knot lines u u r ;r 0;…;k ;v v s ;s 0;…;n form a rectangular grid in the parameter domain [0,1]2.In the following,we will exclude the superscript (p ,q )when the NURBS basis function is of degree (p ,q ).Although the rational B-Splinebasis functions are bivariate,they are not a tensor product in general,in the sense that they cannot be factorised in a product of two univariate rational basis functions.Note that,when all weights are equal the NURBS basis degen-erate to integral (non-rational)B-Spline basis.Therefore,in this case they are tensor product functions.Hence,bivariate NURBS basis functions are the proper generalisation of B-Spline and Be´zier tensor product basis functions.See Fig.3for an example of a bivariate NURBS basis function.Properties of univariate rational basis functions also hold for bivariate rational basis functions.More precisely,•Non-negativity:R ij (u ,v )Ն0.•Partition of unity: ki 0 n j 0R p ;q i ;j u ;v 1.•Non-negativity and partition of unity means that 0ՅR ij (u,v )Յ1.•Local support:For u ;v u i ;u i ϩp ϩ1 × v j ;v j ϩq ϩ1 ;R ij u ;v 0.•Switch on–off effect:In a knot span u i Ϫ1;u i × v j Ϫ1;v j ;the only active basis functions are R r ;s u ;v ;i Ϫp Ϫ1Յr Յi Ϫ1;j Ϫq Ϫ1Յs Յj Ϫ1:When the parameters are moved to a neighbouring interval,a basis function is “switched off”(becomes zero)and another is “switched on”(becomes non-zero).•Differentiability:If the multiplicity of a knot in the u (v )direction is k then the basis function is p Ϫk (q Ϫk )times continuously differentiable in the u (v )direction at this knot.It is infinitely continuously differentiable in the interior of a knot span.•For p,q Ͼ0,R ij (u )has exactly one maximum value in u i ;u i ϩp ϩ1 × v j ;v j ϩq ϩ1 (where it is non-zero).With regard to the influence of weights on the shape of the basis functions,the following can be easily proved •For w ij 0,R ij (u,v ) 0.•For w ij 3∞R p ;qr ;s u ;v1if r ;s i ;j 0if r ;s i ;j:@ 10•For fixed (u ,v ),increasing a weight w ij increases the respective basis function R i,j ,while the rest of the basis functions decrease.3.NURBS curves and surfaces3.1.NURBS and homogeneous coordinatesA geometric model of embedding the projective 3D space in a Euclidean four-dimensional (4D)space (E 4)can be used to define NURBS surfaces [45].Points in E 4are of the form x ;y ;z ;w T .Points in 3D space x ;y ;z T can be embedded in E 4as x ;y ;z ;1 T ,i.e.the hyperplane w 1is considered a copy of 3D space.A NURBS surface is the perspective projection on 3DE.Dimas,D.Briassoulis /Advances in Engineering Software 30(1999)741–751744Fig.2.Influence of changing weight w 3on NURBS basis function R 33.Fig.3.A degree (2,3)bivariate NURBS basis function.space of a tensor product B-Spline surface onto the hyper-plane w 1.This perspective map is defined asM x;y;z;wx=w;y=w;z=w if w 0point at infinity if w 0:@11Note that all points wx;wy;wz;w T map to x;y;z T.The set of all points wx;wy;wz;w T is called the homogeneous coordinates or homogeneous form of x;y;z T.Given a set of3D control points P ij x ij y ij;z ij T,i 0,…,k,j 0,…,n,and a set of weights w ij,i 0,…,k,j 0,…,n associated with the control points,we are in a posi-tion to define a NURBS surface.For this purpose,we use homogeneous coordinates to define the4D pointsh Pij w ij x ij;w ij y ij;w ij z ij;w ij T,i 0,…,k,j 0,…,n.We can then construct a non-rational B-Spline surface in 4D spaceN u;vki 0 nj 0h PijN p i u N q j v ;0Յu;vՅ1; 12where,without loss of generality we have assumed that the knot vectors are of the formU {0;…;0;u pϩ1;…;u mϪpϪ1;1;…;1}:The NURBS surface R p,q(u,v)of degree(p,q)is then defined as the perspective mapR p;q u;v M N u;v ki 0nj 0w ij P ij N p i u N q j vki 0nj 0w ij N p i u N q j v; 13or in a more compact formR p;q u;vki 0 nj 0P ij R p;q i;j u;v : 14The superscript will be dropped when it is clear that the degree of the surface is(p,q).The piecewise linear interpo-lant to the control points P ij is called the control polygon of the surface.Note that when all weights are equal,the surface defined by Eq.(13)becomes a B-Spline surface.If the weights are not equal and there are no interior knots,the surface defined by Eq.(13)becomes a rational Be´zier surface.Eq.(12)can be used to evaluate efficiently the NURBS surface[49].Similarly,a NURBS curve is defined as a perspective map from4D space to3D space or from3D space to2D spaceC uni 0P i R p i u ;0ՅuՅ1: 15The degree p,number of knots( mϩ1)and number of control points( nϩ1)are related by the formula:m nϩpϩ1.Naturally,if the weights are all equal,the NURBS basis functions R p i u (defined by Eq.(7))degenerate to B-Spline basis functions and the curve becomes a B-Spline curve.3.2.PropertiesThe most significant properties of NURBS surfaces are:•Generalisation:When all weights are equal,the surface defined by Eq.(13)becomes a B-Spline surface.If the weights are not equal and there are no interior knots,the NURBS surface becomes a rational Be´zier surface.•For afixed parameter value v a and u ranging in[0,1], R(u,a)is a NURBS curve of degree p with weightsw inj 0w ij N q j a ; 16•and control pointsP inj 0w ij N q j aw iP ijnj 0P ij R q j a : 17•The NURBS surface interpolates the four corner control points P00,P0n,P k0,P kn.•The derivatives at the corners are the same as the deri-vatives of the boundary curves R(0,v),R(1,v),R(u,0), R(u,1)at their endpoints.•Differentiability:Same differentiability properties as the basis functions.•The basis functions switch the control points on and off.•Strong convex hull property:If u;v ʦ u i;u iϩ1 × u j;u jϩ1 ,then R(u,v)is in the convex hull of the control points P rs,r iϪp,…,i,s jϪq,…,j.•Locality:A movement of the control point P ij affects the surface only in the interval u i;u iϩpϩ1 × v j;v jϩqϩ1 .•Affine and projective invariance:A NURBS surface is affinely and projectively invariant,i.e.transforming the surface by an affine or perspective transform is equiva-lent to transforming the control points.•Increasing a weight w ij pulls the surface towards the control point P ij.For more on the influence of weights on NURBS curves and surfaces,see[50].One important property of NURBS curves that surfaces do not seem to share is the variation diminishing property [51].3.3.Advantages and disadvantages of NURBSNURBS are very popular both in the academic and commercial geometric modelling world.Indeed,they offer advantages which make them attractive for design applica-tions•They are more general than Be`zier and B-Spline curves and tensor product surfaces.E.Dimas,D.Briassoulis/Advances in Engineering Software30(1999)741–751745•Evaluation is straightforward,fast and computationally stable.•They offer a common mathematical representation for free-form surfaces and commonly used analytical shapes such as natural quadrics,torii,extruded surfaces and surfaces of revolution.•They are affine(rotation,scaling,translation),parallel and perspectively invariant as well as invariant under shear transformations.•It is easy to change their shape through the manipulation of control points,weights and knots.•Degree elevation,splitting,knot insertion and deletion and knot refinement offer a wide range of tools to design and analyse shape information.Some of the disadvantages of NURBS over traditional representations are•Bad choice of weights can lead to bad curve/surface parameterization.•More storage is needed to define traditional shapes,such as a circle or a sphere.•Some algorithms are numerically unstable(e.g.inverse point mapping).•Some algorithms work better with other forms than with NURBS,puting the intersection curve of two surfaces.•Point member classification is a difficult problem for parametric surfaces.Therefore,it is particularly difficult to include NURBS as nodes in a constructive solid geometry system.monly used surfaces and their NURBS representationThe most common surfaces used in CAGD are the natural quadrics(plane,sphere,cylinder,cone),torii,ruled surfaces,extruded surfaces and surfaces of revolution. Therefore,it is useful to understand their NURBS represen-tation and characteristics.For the NURBS representation of conic curves,see[52].4.1.Quadric surfacesPlaneA planar surface patch can be obtained by a bilinear NURBS surface whose control points are on the corners of the patch. SphereA sphere is a surface of revolution.It can be obtained by revolving a semicircle in,say,the xz-plane with the endpoints of the semi-circle located on the z-axis,around the z-axis.CylinderA cylinder can be obtained by linear extrusion(see later). ConeA cone is a special case of the cylinder,in which one of the curves has degenerated into a point.Therefore,it is obtained by linear extrusion.General quadricsNon-rotationally symmetric quadrics are obtained by apply-ing affine transforms to rotationally symmetric quadrics, which are surfaces of revolution(see later).4.2.Extruded surfacesAn extruded surface S(u,v)can be defined by a profile curve in the u-direction asC uni 0P i R p i u ;0ՅuՅ1: 18which is then extruded in the direction of a unit vector n for a distance d.Therefore,it has the following characteristics •Forfixed u a,the u-isoparametric curve S(a,v)is a straight line between the points C(a)and C(a)ϩd n.•Forfixed v b,the v-isoparametric curve S(u,b)is a translation of C(u)by d n,i.e.S(u,b) C(u)ϩd n.As NURBS curves and surfaces are affinely invariant,any v-isoparametric curve has the same control points as C(u) translated in the appropriate direction and distance.The representation of an extruded surface isS u;vki 01j 0P ij R p;1ij u;v 19over the knot vectors U(the knot vector of C(u)),V {0,0,1,1}(the knot vector of a straight line segment),control points P i,0 P i,P i,1 P iϩd n for i 1,…,k and weights w i0 w i1 w i.4.3.Ruled surfacesGiven two NURBS curvesC1 uk1i 0P1i R p1i u and C2 uk2i 0P2i R p2i u20a ruled surface is one which is obtained by linear interpola-tion between C1and C2.Therefore,it has the following characteristics•Forfixed u a,the u-isoparametric curve S(a,v)is a straight line between the points C1(a)and C2(a).•S(u,0) C1(u)and S(u,1) C2(u).Assuming that k1 k2 k(same number of knots in each curve),p1 p2 p(basis functions of the same degree)and U1 U2 U(same knot vectors),the desired representation for a ruled surface isS u;vki 01j 0P ij R p;1ij u;v ; 21E.Dimas,D.Briassoulis/Advances in Engineering Software30(1999)741–751 746where the knot vectors are U ,V {0,0,1,1}and the surfacecontrol points P i ,0,P i ,1come from the first and second curve,respectively.More precisely,the surface has control points P i ;0 P 1i ;P i ;1 P 2i ;22and weights w i 0 w 1i ;w i 1 w 2i :23If one of the aforementioned conditions are violated,thesituation requires some fixing:1.If p 1 p 2use p max(p 1,p 2)and degree raise the lower degree curve to degree p .Degree raising does not change the geometry of a curve.It merely allows us to write a curve of some degree as a curve of a higher degree.For illustrative purposes,we present degree raising formulaefor a rational Be `zier curve of degree p to degree p ϩ1•The control points of the p ϩ1degree curve aredefined in terms of the control points P i of the p degreecurve P p ϩ1 iiw i Ϫ1P i Ϫ1ϩ p Ϫi ϩ1 w i P iiw i Ϫ1i:24•The new weights become w p ϩ1 ii p ϩ1w i Ϫ1ϩp Ϫi ϩ1p ϩ1w i : 25For degree raising of NURBS curves,the Boehm or Osloalgorithm can be used [53].2.When the degrees of the curves are the same,a common knot vector U U 1 U 2must be found.Simply,let U be the union of U 1and U 2.Knot insertion [53]can be used to represent the two curves in terms of the common knot vectors (the parameterization and geometry of the curves remain unchanged).Now,the problem is simplified to finding a ruled surface between two curves of the same degree and common knot vector.The cone is a special ruled surface between a base curve C 1and a degenerate curve C 2(which is really the vertex P of the cone).The degenerate curve C 2can be represented as a curve of the same degree as C 1,all control points equal to P and all weights constant.The desired cone is a ruled surface between C 1and C 2.4.4.Surfaces of revolutionSurfaces of revolution are obtained by revolving a planar curve about an axis.Suppose that C vn i 0P i R p i v ;0Յv Յ1: 26is a curve in the xz -plane,with knot vector V ,weights w i ,i0,…,k and control points P i x i y i z i T .A surface of revolu-tion S (u ,v )is obtained by revolving C (v )around the z -axis.Therefore,it has the following characteristics•For fixed v a ,the u -isoparametric curve S (u ,a )is a circular arc with centre on the z -axis and lying in a plane perpendicular to the z -axis.•For fixed u b ,the v -isoparametric curve S (b,v )is the curve C (v ),rotated some angle around the z -axis.To define a surface with such characteristics,we need to combine a circle definition with the definition of C (v ).However,there are several NURBS representations for the circle which give rise to different representations of the revolved surface.In different representations,different control points,weights and knot vectors are used to describe a circular arc.Different arcs are then pieced together to form a full circle [45,48].Suppose we want to define a full surface of revolution.AE.Dimas,D.Briassoulis /Advances in Engineering Software 30(1999)741–751747Fig.4.NURBS profile curve and controlpolygon.Fig.5.Control polygon of the surface of revolution defined by the curve in Fig.4.。
Samson S9HD 三云滑行音响系统 说明书
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S9HD Owner’s Manual
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S9HD Owner’s Manual
The S9HD has it all --Big power handling, big projection, combine with “Ultra Hi-Definition Sound”. It’s unique design offers superior performance in a enclosure that is still manageable and compact. The Samson sports sound quality, form factor, power handling and fit and finish are un-
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