Hi there,
I noticed that during an export of an object into obj format the faces (“f”) look like this :
f 458/1/1203 1234/2/1203 1828/3/1203
Note the vertex normal index which does not change.
Obviously, this must be wrong, since the faces have a different vertex normal at each vertex. (In my case this was a sphere.) This keeps me from exporting smooth objects.
Is this a bug in the exporter, or am I doing something wrong?
Regards,
Marc
Its not a bug. faces that are set solid all use the same normal, faces that are set smooth use vertex normals.
Hi!
There’s a bug (for sure) related to vertex normals in current CVS versions.
I filed a report in September 2006 in the bugtracker. It contains a .blend file showing the error:
http://projects.blender.org/tracker/index.php?func=detail&aid=5020&group_id=9&atid=125
Obviously vertexnormals are not updated correctly if a vertex is modified with python.
Smooth shading is incorrect in this case.
I don’t know if this has something to do with your problem though…
Michael
I dont think that report is even a bug. read my reply on the tracker,
exporting and importing normals is different so I dont they are the same issue,
Are the faces smoothed your exporting?
if so, can you try export with “high quality normals”? - see if that yelds a different result.
You’re right Cambo - calcNormals() works fine.
It’s not really a bug then - but at least it’s not well documented. In Blender 2.42, mesh.update() was the function to call. Now it’s mesh.calcNormals(). This is a change in functionality - it can break existing scripts. Therefore i’d say it’s something that really needs to be documented. Maybe you can add a line of text in the mesh.update() documentation?
Something like “Caution: mesh.update() does no longer updates vertex normals - use calcNormals().”
It’s not easy to keep track with all those api changes if you’re not constantly checking and testing. Your post with the changes since 2.42 is really a good idea - thanks!
Michael