About Tessellation
When creating a mesh out of a CAD model, Pixyz Plugin uses several parameters to create a surface mesh:
- Max SAG: The maximum distance between the geometry and the tessellation (also called "Chord error"). This parameter ensures that the mesh is similar enough to the original analytical surface (exact geometry).
A low value means that a very fine mesh is created. The distance values are expressed in millimeters.
- Max Angle: The maximum allowed angle between normals of two adjacent polygons (on the same face). This provides more precision on small radius fillets.
Adjust the "Max angle" parameter to keep enough polygons in high curvature areas whose radius is lower than the "Max Sag" value: fillets and chamfers for example.
- Max length: Used to control the length of a polygon (edge).
For a rendering usage, it is often not recommended to use the "Max Length" parameter. It increases the polygons count without significant improvement on the visual aspect. But in case of very long objects (a plane body, a train cabin…), this setting can avoid lighting artifacts caused by too long polygons.
NOTE The "Max Length" parameter for the tessellation algorithm is not used/available in all Pixyz solutions (for example inPixyz Plugin for Unity).
In the example below, the « Max angle » parameter has improved fillet precision by adding a row of polygons without increasing the polygon count for the yellow piece contour:
