2.0 KiB
Glossary
-C-
Coincident
Coincident vertices share the same coordinate space, but are incident to two separate edges.
-D-
Degenerate triangles
A degenerate triangle does not have any area.
-I-
Incident
When an edge connects two vertices, those vertices are both incident to the edge.
-M-
Manifold and non-manifold geometry
Manifold geometry is well-formed and could exist in the real world. Non-manifold geometry can cause errors and could de-stabilize your project. The following are examples of non-manifold geometry:
- Inner faces (faces enclosed inside another set of faces)
- Overlapping faces (occupying the same space)
- Faces that bisect another mesh
- Self-intersecting faces
-Q-
Quad (quadrangle)
Most polygons are "triangulated", or divided into faces with three edges. However, ProBuilder supports four-sided faces, or "quadrangles" in many cases. "Quad" is the abbreviation for "quadrangle".
-W-
Winding order
Winding order determines how a polygon's vertices are rendered (clockwise vs. counter-clockwise). A clockwise winding order is sometimes called "right-handed" and a counter-clockwise winding order is sometimes called "left-handed". In left-handed coordinate systems like Unity, where the y-axis is "up", counter-clockwise winding is front-facing. For right-handed systems, the rendering order is opposite .
Winged edge
When three or more faces meet at a boundary, the vertex where they meet is coincident with multiple faces and edges. The WingedEdge is a structure that holds information about a face, an edge, and a vertex at that boundary. It also provides a list of coincident edges so you can use the EdgeLookup to access information about them through scripting.