Facet

Format

facet normal
  outer loop
    vertex
    vertex
    vertex
  endloop
endfacet

Stereolithography CAD file format. The normal vector and vertex coordinate are recorded.

Example

facet normal 1.000000e+00 0.000000e+00 0.000000e+00  
  outer loop
    vertex -1.000000e+00 -1.000000e+00 1.000000e+00  
    vertex -1.000000e+00 1.000000e+00 1.000000e+00  
    vertex -1.000000e+00 1.000000e+00 0.000000e+00  
  endloop
endfacet

The normal vector of the triangle is (1,0,0), while the vertices are (-1,-1,1), (-1,1,1), and (-1,1,0).