Autodesk 663B1-05A111-1001 User Guide - Page 277

12 | Basics Menus Reference > Modify > Convert > NURBS to Polygons Outputting to triangles or quads Type Select the type of polygons to use when you convert NURBS geometry to polygonal data. If you select Triangle (the default), 3-sided polygons are created. If you select Quads, 4-sided polygons are created. Triangle polygon type. Quad polygon type. Note When you tessellate a trimmed NURBS surface, some 3-sided (triangle) polygons may be created along the trim edge even when the option is set to Quads. Choosing a tessellation method Tessellation means that you create a set of polygons from NURBS geometry. Each tessellation method provides you with options that let you control the resulting polygonal surface. There are four tessellation methods: "Standard fit", "General", "Count", and "Control Points". Standard fit Standard Fit is the default tessellation method. It is "adaptive" tessellation, meaning that the following options are used to determine when to stop the tessellation. For example, the tessellation stops at the Fractional Tolerance value you set. If there is an edge shorter than the Minimal Edge Length, the tessellation stops on that edge. If the surface is flat enough within the edge (the specified chord/ height ratio is small enough), the tessellation stops there. Chord Height Ratio The Chord Height Ratio is the ratio between the maximum distance of the curve from the polygon edge used to approximate it and the chord length. The chord length is the linear distance between two polygon vertices. Basics 277