I''m working on my own game engine. The other guy on the project is the "art guy" and he wants to use Maya and NURBS. Anyone have any suggestions for how to get models using NURBS from Maya to an OpenGL app? I''ve been using .obj''s so far just because they are so damn easy to parse. Apparently, though, the .obj exporter that ships with maya does not support NURBS. What I''m basically looking for here is: a) Where do I get a Maya plugin that exports to .obj''s and saves nurbs OR if none exists how large of a task is it to write one myself b) What file format do you recommend to use to get stuff from Maya?

well, i dont use maya, but in 3dsmax you can
convert nurbs objects to mesh''s before you export them..
maybe there is a similar feature in maya

-eldee
;another space monkey;
[ Forced Evolution Studios ]

Yeah, I''ve got them rendering in the engine as meshes, but I want to export them and use them in the game as NURBS.

Maya has a very cool and powerful scripting feature called MayaScript. Using MayaScript you can write function to export a nurb to a file. You''re still going to have to have nurb code in your game. And you''re going to have to figure out a way to re-associate it with the model.

Hope this helps: http://www.oroboro.com/rafael/maya.html

Cheers,
Eoin,

quote:

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Original post by Eoin
Hope this helps: http://www.oroboro.com/rafael/maya.html

Cheers,
Eoin,

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Thank you, that was fantastically helpful.

Using NURBS has some advantages and some major disadvantages. For a start don''t think about using gluNurbs because it has no hardware acceleration and is increadibly slow. Usually it is best to use lazy evaluation when calculating Nurbs surfaces and cache up as much of the calculations as possible. It''s liable that you will see big performance increases over polys if using skinned animation. Draw the data using vertex arrays and triangle strips.

One thing worth taking note of, for some reason when querying the Nurbs data in maya, it will always return less knots than actually exist in both directions. The way around it is to duplicate the first and last knot values in both surface directions.

Additionally, people who like modelling in NURBS (very few thankfully) have a tendancy to use projected textures on a lot of their surfaces. This will therefore require you to get hold of the projection transform and you''ll have to duplicate that in code. (possibly getting openGL to generate that for you). If the characters have been modelled in this way and are intended to be animated either using skinning or

The additional problem is the amount of textures that are required. Each Surface requires a texture across it''s entire surface unless you are using projections, so the texture wastage is quite high.