【转帖】order of vertex-data in polyfacemesh
 

order of vertex-data in polyfacemesh
order of vertex-data in polyfacemesh
i used odreadex to create the following output:
code:
acdbpolyfacemesh, 9582
n verts: 4 n faces: 2
acdbpolyfacemeshvertex -720.682, 112.173, 4
acdbpolyfacemeshvertex -707.112, 111.663, 4
acdbpolyfacemeshvertex -720.682, 111.663, 4
acdbpolyfacemeshvertex -707.112, 112.173, 4
acdbfacerecord vertex indices: -1 2 3 0
acdbfacerecord vertex indices: 1 4 -2 0
this simple example should be a quadrangle, but i don't know in which order i must read the vertex-data
here are my questions:
- why are there 2 vertex indices?
- what does the negative value in a vertex indice mean?
thanks!
jörg nestele
negative vertex index indicates that edge of face is invisible. zero index (last of 4 indices) indicates that where is no 4-th vertex - face is triangle.
in your mesh you have to triangle faces. the coincident edges of 2 triangles are invisible so you see them as one quadrangle.
sergey slezkin

a quadrangle consists of 2 triangles with invisible vertex? thats confuse!
but i understand your description. thank you!!!