Alpha blending issue:

The tree model is modeled in Maya using separate TGA files for the model's texture color and the model's texture alpha transparency.

In Maya, the alpha blending on the model works correctly and the negative space is transparent.

The model being used was exported as FBX then used in XNA.

The lines used to draw the model in XNA are:

 graphics.GraphicsDevice.RenderState.AlphaBlendEnable = true;
        graphics.GraphicsDevice.RenderState.SourceBlend = Blend.SourceAlpha;
        graphics.GraphicsDevice.RenderState.DestinationBlend = Blend.InverseSourceAlpha;

These lines have worked fine for other models with transparencies, but now with a model using alpha transparency textures, the polygons that include alpha transparency textures are appearing partially transparent, but not according to the texture's alpha transparency value. The polygons that appear partially transparent should appear opaque in positive alpha value areas and transparent in negative alpha value areas.

What is it that I'm missing in order to set the alpha blending settings for the alpha transparency textured models in XNA?

Any help would be greatly appreciated. Thanks and have a great day.

• Make sure that the alpha texture is exported by Maya along with the color texture.
  
• Write a custom content processor that takes care of the extra alpha texture in the fbx file and assign that to the correct variable in your effect (or however you want to store it.)
• Make sure that the alpha texture sampled in your pixel shader and the value is outputted in the alpha channel.