Writing a custom shader to help draft models for plastic injection.

[Lwmusings]

Hello everyone,

 

Long time lurker, just barely getting to posting. I'm looking into writing a shader for 3dcoat and wondering if I could get the communities help or advice?

 

I'm using 3Dcoat to create models for plastic injection. The auto draft tool is nice for quickly eliminating undercuts but I'd like to create a shader that highlights areas of undercut for manual fixing. It would be very handy for initially picking the draft angle. For example you could designate the Z axis as the direction of the draft for the shader. You then rotate your model in space looking for the angle that will require the least modifications to the model.  It also helps identify places where a little tweak to the details of your model eliminates the "smearing" or "stretching" effects of the auto draft tool.

It may sound a little complicated but the shader is actually very simple. I created a surface that does it in openGL with Lightwave using simple gradients.

 

All that is needed is a shader that colors the model based off the direction the normals are facing. For example triangles facing Z- would get tinted a red hue and triangles facing Z+ would get tinted a green hue. Triangles that are very near perpendicular to the z axis ideally get shaded both (yellow). This would require an angle of tolerance, which could be hardcoded in the shader.

So I guess my first question would be does that sound achievable? And if so does anyone know any good places to learn HL Shading Language to help me get started?

[Carlosan]

This shader helps you ?

http://3d-coat.com/forum/index.php?showtopic=4284&page=1