> Another thing, I believe that for the rendering, Carrara transform the
> 3dm in "poly" in internal for rendering
> It's not a "nurbs renderer" :)

This is not necessarily bad though - the most standard way to render NURBS is to convert it to polygons. There are only very few "true NURBS renderers" out there because rendering NURBS directly tends to be extremely slow.

There are also some other problems with rendering directly other than speed - during the construction of NURBS objects it is normal for there to be very slight gaps (within the modeling tolerance, typically like 0.01 or 0.001) between intersected surfaces. When rendering the NURBS directly, it is possible to have these gaps show up as cracks when zoomed in on spots of the model.

A good quality conversion to polygons will take care of this crack problem because it will generate polygons that are completely sealed together along shared edges of the NURBS model.

- Michael

Michael, I'd like to try to do an exporter to RIB for use in the free 3Delight engine. Any docs you can throw my way?

Or would you suggest trying to read the 3DM file format instead and converting that to RIB?

Any direction would be appreciated.

-TS-

> Michael, I'd like to try to do an exporter to RIB for use in the free
> 3Delight engine. Any docs you can throw my way?

Do you mean docs for the RIB format, or do you mean docs for doing a MoI exporter?

There aren't any docs for the latter right now, because MoI doesn't yet have a pluggable system for doing exporters yet.


> Or would you suggest trying to read the 3DM file format instead and converting that to RIB?

At some point in the future when MoI does have a plug-in system for doing exporters (not really sure when this will happen), I was thinking of exposing the NURBS data to plugins in the 3DM/OpenNURBS format.

So that would be pretty much equivalent to doing a standalone 3dm2rib.exe type converter anyway, so that would probably work well as a first step.

The OpenNURBS toolkit is pretty straightforward for reading .3dm files - you can get the toolkit here: http://opennurbs.org/, and there should be an example_read sample that would be a good starting point.

I should be able to help you over any difficult spots, just let me know.

- Michael