exporting smooth normals

[GoogleCodeExporter]

It seems that lib is ignoring config settings and whatever I try to export 
model I got flat version (no real vertex normals).

I've tried file to file conversion and blob to file (code below).

NormalSmoothingAngleConfig config = new NormalSmoothingAngleConfig(40.0f);

importer.SetConfig(config);

ExportDataBlob blob = importer.ConvertFromFileToBlob(fileName, 
"obj",PostProcessSteps.GenerateSmoothNormals /*with or without doesn't change 
anything*/);

Original issue reported on code.google.com by z.janke...@gmail.com on 11 Aug 2013 at 8:06

[GoogleCodeExporter]

Well all the library is doing is forwarding that property config to the 
unmanaged importer, so the wrapper doesn't play a role in the vertex normal 
generation. Couple of ideas:

-Does the source model already have normals? Per to the documentation, the post 
process normal generation is skipped if they are present.

-Is the smoothing angle too low? Face normals that exceed the angle will not be 
smoothed, so those vertices will also have a hard/flat look.

I would recommend loading your model up in the Assimp Viewer:

http://assimp.sourceforge.net/main_viewer.html

Original comment by nicholas.woodfield on 13 Aug 2013 at 1:57

[GoogleCodeExporter]

Your library is generally - cool!
There are two problems:
1. if model loader class (3ds, obj,stl ..) generate normals (usually those are 
surface normals)- library will IGNORE any attempt to generate vertex normals.

First line in:
bool GenVertexNormalsProcess::GenMeshVertexNormals (aiMesh* pMesh, unsigned int 
meshIndex)

is:
    if (NULL != pMesh->mNormals)
        return false;

While you don't have (your .net code) influence on dll library you can make few 
improvement by adding more control over conversion (ConvertFrom*) because that 
doesn't work as it should.

I have had luck with:
Scene 
model=importer.ImportFile(fileName,PostProcessPreset.TargetRealTimeMaximumQualit
y); 
Then I simply use data from model.Meshes.

I believe problems with ConvertFrom* functions are that there's no possibility 
to set all flags via importer.SetConfig(config); so things like joining 
vertices can't be issued.

Thanks for this library!
Z.

Original comment by z.janke...@gmail.com on 13 Aug 2013 at 2:26

[GoogleCodeExporter]

Both convert and import follow the same process in preparing config properties 
and post processing.

I think there's some confusion on how to setup these. The configs are 
name-value pairs and you can set as many as you'd like via SetConfig. The join 
identical vertices option is not a config, but a post process step so it has 
nothing to do with SetConfig(), although some configs serve as input to a post 
process step. That pp step most likely clears existing vertex normals, which is 
why TargetRealTimeMaximumQuality is working out. You can just as well have 
specified:

PostProcessSteps.GenerateSmoothNormals | PostProcessSteps.JoinIdenticalVertices

The preset like the one you used have both of these flags set. 

There *is* a chance that the problem may lie with the data in the export data 
blob. I don't know how the obj exporter is written (unlikely, although 
possible, it may not be writing out the correct normals). The export data blob 
contains an export file format, not the same data structure you see returned 
from ImportFile. 

Original comment by nicholas.woodfield on 13 Aug 2013 at 3:32

[GoogleCodeExporter]

Original comment by nicholas.woodfield on 21 Aug 2013 at 1:42

• Changed state: WontFix