Well, I read your post several times and I'll be honest in that I don't fully understand your scenario, but you stated that you are seeking a method for detecting line-to-rectangle intersections, so I'll just talk briefly about that. I think the best way to do that would be to define each edge of the rectangle as a line using ...

Well in my opinion, half circles would be a better choice in your situation because the points where the half circles connect to the big circle would have a smooth tangent transition. If you use sine waves, the connection points would have a more abrubt change in direction. Also, the half circles are easier to implement.

I'm not sure if all of the extensibility features are available for express versions of Visual Studio, but I believe you should be able to find the answers to your questions on one of these pages: http://msdn.microsoft.com/en-us/vsx/default.aspx http://msdn.microsoft.com/en-us/library/bb166441.aspx

I don't think you'll find a simple render state setting that will get the job done. However, you can probably write a pixel shader that examines the colors in the textures and then outputs whatever color you want.

Interesting question. Can you post the exact wording of the error you are getting?

The free Softimage XSI Mod Tool can import EPS/AI files as curves that you can then use to create models. Other apps such as Blender may have similar import capabilities. You can get the Mod Tool here: http://creators.xna.com/en-US/partners

One more thought... You don't even really need to track the tangent vector. You can just track the ship's heading angle and update it appropriately relative to the big circle and the half circles. Once the ship is rotated to the correct heading, you can translate it to the correct point in space on either the big circle or the half circles.

Well my calculus is a bit rusty, but my recollection is this: The derivative of a curve function is another function whose solution for a given value of X represents the slope of the original function at that same value of X. The derivative of sin(x) is cos(x) as shown here: http://en.wikipedia.org/wiki/Sine#Sine In other ...

So you have the model offset somewhere in the XY plane and you want to rotate it around the Z axis? Does the newPos variable represent the position of the model? What direction are you wanting to have the model face as it rotates? Give as much info as possible about what you want to accomplish.

My guess would be that the duplicate geometry exists in Maya but is hidden. View the Outliner in Maya to see if you can find and delete the unwanted items. If there is a modeling relationship between the hidden and the final geometry, you may need to first delete the history on the final geometry.