Autodesk 663B1-05A111-1001 User Guide - Page 278

12 | Basics Menus Reference > Modify > Convert > NURBS to Polygons Basics 278 Chord Height Ratio value 0.05. Chord height Ratio value 0.1 (default). Valid values range between 0 and 1, where larger values result in fewer polygon vertices. For example, the default value, 0.1, means that the height must be larger than 1/10 of the chord length before additional edit points are created. Fractional Tolerance The Fractional Tolerance value determines the degree of accuracy maintained between the original surface and the interpolated polygonal surfaces. The default is to be accurate to within 0.01 units, where a unit refers to the current unit of linear measure (the default unit of measure is centimeters). Therefore, at no point will the polygonal surface be more than the tolerance distance away from the original NURBS surface. In this next example, notice how you can enhance the polygonal surface's accuracy when you change the Fractional Tolerance value from 1 to 0.01. Value set to 1.0. Default Fractional Tolerance value (0.01). Minimal Edge Length Enter a value or use the Minimal Edge Length slider to set the minimum length of the edges of the triangles or quads that are created. 3D Delta The 3D Delta value determines the 3D spacing for U and V isoparms on a surface that makes up the initial grid for the tessellation. In the following example, the 3D Delta value is changed from the default 0.1 to 1.0.