double sided faces?

Blender3D · Post by **Blender3D** » Thu Aug 14, 2008 11:51 am

Hallo, guys

I have a short question about the engine. I modified the 08.SpecialFX example so that only the light with his billboard an the room was left. Then I added a tree made by myself to test shadows. Therefore I used the *.3ds fileformat exported from Blender. And everything works well but the shaows do not look good enought. I guess that double sided faces would solve my problem. Does anyone know if Irrlicht supports them and/or how they are activated?

--Blender3D

PS:
I know my english is horrible.

JP · Post by JP » Thu Aug 14, 2008 12:03 pm

you can turn back face culling on/off on a nodes material with something along the lines of node->setMaterialFlag(EMF_CULL_FACE, false);

Is it a shadow volume you're using? They're quite poor and have bad performance, you're better off using a shader, there are a few in the projects forum that you can use, so try one of those out.

hybrid · Post by **hybrid** » Thu Aug 14, 2008 12:03 pm

You mean material.BackFaceCulling=false?

Blender3D · Post by **Blender3D** » Thu Aug 14, 2008 12:27 pm

Yes, I am using addShadowVolumeSceneNode(); but it does not compile with
anode->setMaterialFlag(EMF_CULL_FACE, false); because it says that EMF_CULL_FACE was not declared in that scope.

--Blender3D

JP · Post by JP » Thu Aug 14, 2008 1:00 pm

That was a guess on my part, either it needs video:: in front of it or i just remember the name wrong, check the docs for the correct parameter.

hybrid · Post by **hybrid** » Thu Aug 14, 2008 1:24 pm

EMF_BACK_FACE_CULLING is the proper enum value. And it's in video namespace.

Blender3D · Post by **Blender3D** » Thu Aug 14, 2008 7:41 pm

Thanks for replying guys...

I can tell you: The model looks much better now, but the shadow is as bad as before. The Shadow looks better, if I take the model twice: once with normals outside an once with normals flipped. But that gives very very poor performance.

Another question: How can faces be smoothed in Irrlicht?

--Blender3D

hybrid · Post by **hybrid** » Thu Aug 14, 2008 8:59 pm

The 3ds file format is loaded with duplicated vertices in Irrlicht. This means that no vertices or edges are shared among the faces. The shadow calculation relies on this fact, though. Hence, problems are expected. You can try to use a different format. Another way could be the MeshManipulator method createMeshWeldedVertices. You can also set a separate, simplified mesh for shadow generation in the latest SVN trunk version of Irrlicht (upcoming for Irrlicht 1.5). This could help if you have problems with material properties when exporting to other file formats.

Blender3D · Post by **Blender3D** » Sat Aug 16, 2008 3:30 pm

Thanks for replying guys...

--Blender3D