Quote Originally Posted by chronozphere
What if certain FVF data is used in the effect-file, but isn't present in the mesh that is to be rendered with it.
The result is most likely unpredictable. You should not rely on it. Check that the mesh vertex declaration has all necessary fields before passing it to shader, or use a different shader that doesn't need these fields.

Quote Originally Posted by chronozphere
Will the missing data be replaced by zero's or will i get an error?? Are there routines available to find out which FVF attributes a mesh must have, when using that shader??
Not really. You should check both the shader code and the vertex declaration of your mesh to make sure that both can function together.

Also, if you are using shaders, why do you still use FVF? :shock: