Hi Radiance,
quote: smoothing groups are not used to recreate any vertex normals.
they are only used to define the bounds of interpolating the provided vertex normals during rendering.
That's not proper vertex normal handling.
Again I will quote directly from the OBJ spec:
quote:
vn i j k
Polygonal and free-form geometry statement.
Specifies a normal vector with components i, j, and k.
Vertex normals affect the smooth-shading and rendering of geometry.
For polygons, vertex normals are used in place of the actual facet
normals. For surfaces, vertex normals are interpolated over the
entire surface and replace the actual analytic surface normal.
When vertex normals are present, they supersede smoothing groups.
i j k are the i, j, and k coordinates for the vertex normal. They
are floating point numbers.
Note the part that I have put in bold - it is intended that when vertex normals are present in the OBJ file, they are used to shade the polygon and smoothing groups are completely unused and should not affect the rendering in any way.
If you read the vertex normals from the file, all the normals for every face are already defined and there is nothing you need to do with smoothing group processing.
Just take the normals that the face is using and use them.... Don't modify them by break angles or smoothing groups or anything like that.
Maybe you are using a completely different term for what "vertex normal" is or something?
- Michael |
