The order of vertices in each triangle will define the face normal. ashape3d objects do not seem to do this in the way that mesh3d objects do. Rather there is some logic in the calculation of surface normals triangleNormals C function called by surfaceNormals R function that uses the tetra field.
The order of vertices in each triangle will define the face normal.
ashape3dobjects do not seem to do this in the way that mesh3d objects do. Rather there is some logic in the calculation of surface normalstriangleNormalsC function called bysurfaceNormalsR function that uses the tetra field.