Point cloud based design and manufacturing

传统的CAD/CAM软件使用简单的“CSG”块等基元结合布尔交等操作来创建3D模型。 雕塑B样条曲线和曲面可以添加，并“评估”产生一个拓扑集的“B-rep”有界，体积封闭的表面。 在实践中，CSG到B-rep评估过程涉及不精确的表面/表面相交，并且基于浮点舍入的交换可靠性问题仍然存在。 同时，立体视觉和激光三角测量系统，用于将设计概念模型等转换成密集的点云，已经越来越被接受。 这些点云被转换为拟合的B样条曲面，并被“流线化”以平滑曲率“凹凸”。 B样条的使用降低了数据存储要求，并与现有的IGES/STEP交换标准兼容。 然而，最终，CAD模型将转换回点样式表示。 图形硬件是基于快速显示的多边形，创建的“镶嵌”从B-REP模型。 对于制造业，快速成型机需要基于STL三角形的文件表示。 最终，计算机数控（CNC）加工需要创建由（短）线性运动组成的刀具路径。 它们固有的可靠性，加上不断提高的计算机速度和内存可用性，已经创造了CAD研究界从CSG/B-rep和B样条模型到完全点云表示的趋势。 拟议的研究将利用这一新兴趋势，并扩展早期，但成功的申请人研究从立体视觉和激光三角测量为基础的钣金应变分析，更一般的表面灰度和颜色测量，点云为基础的碰撞检测，快速原型表面着色使用3-D坐标测量机（CMM）安装喷墨打印机头。 其他潜在的应用包括金属板和铜印刷电路板的电化学蚀刻、通过喷墨细胞沉积的计算机辅助组织工程（CATE）以及使用医学计算机断层扫描（CT）和磁共振成像（MRI）扫描数据规划的触觉手术。

Conventional CAD/CAM software uses simple "CSG" block, etc. primitives combined with Boolean intersect, etc. operations to create 3-D models.  Sculptured B-spline curves and surfaces can be added, and "evaluated" to yield a topological set of "B-rep" bounded, volume enclosing surfaces.  In practice, the CSG to B-rep evaluation process involves inexact surface/surface intersections, and floating point round-off based exchange reliability problems remain.  Concurrently, stereo vision and laser triangulation systems, used to digitize design concept models, etc. into dense point clouds, have grown in acceptance.  These point clouds are converted to fitted B-spline surfaces and "faired" to smooth out curvature "bumps".  Use of B-splines reduces data storage requirements, and is compatible with the existing IGES/STEP exchange standards.     Ultimately, however, CAD models are converted back to point style representations.  Graphics hardware is based on rapid display of polygons that are created by "tesselating" from the B-rep model.  For manufacturing, Rapid Prototyping machines require STL triangle based file representations.  Ultimately, Computer Numerical Control (CNC) machining requires creation of tool paths that consist of (short) linear motions.  Their inherent reliability, combined with ever increasing computer speed and memory availability, has created a CAD research community trend away from CSG/B-rep and B-spline models to wholly point cloud representations.  The proposed research will harness this emerging trend, and extend early but successful applicant research from stereo vision and laser triagulation based sheet metal strain analysis to more general surface gray level and color measurement, point cloud based collision detection, and rapid prototype surface coloring using a 3-D Coordinate Measuring Machine (CMM) mounted inkjet printer head.  Additional potential applications include electrochemical etching for sheet metal and copper printed circuit boards, Computer Aided Tissue Engineering (CATE) by inkjet cell deposition, and haptic surgery planned using medical Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) scan data.