I can't figure out how to use the GetUDirection method of the IRenderMaterial class.  The method signature looks like this: GetUDirection(out double UDir).  The help file defines UDir like so: Array of doubles representing the U direction for the texture-based appearance (see Remarks).  But UDir is not difined as an array of doubles in the method signature.  This looks like an error to me.  Or I am very confused??

I am using C#.  I am trying to programattically apply a texture to a face.  The texture is a wood grain pattern so it is important I apply the texture oriented in a certain direction.  It looks like I can apply the texture using the SetTexture method of the IFace2 class and that I can apply an orientation angle when I create the texture using the CreateTexture method from ModelDoc2.Extension.... but what is the reference angle for the CreateTexture method?  As in, if I set the angle to 0 when I create the texture, what direction will the texture be applied in reference to the face I apply it to?  I thought I might find the reference angle by looking at the U Direction from the surface on the face.  However, that does not appear to be the case. 

I am guessing in the dark here so any information you can give me about how to apply a texture to a face in a known orientation would be much appreciated.