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。

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.