Hi,

I am looking at using Mantra to produce some volume rendering similar to those seen in packages like OpenDX/AVS but at a much higher quality.

Can anyone point me to some examples I can start of with?

I generally have a collection of point and scalar pairs, I provide a LUT to map/transfer the scalar value to a color ramp.

Would it be easier if I translate my information into the Houdini geo/bgeo format before reading it into Houdini?

Regards

I posted this to the sidefx mailing list a while back to illustrate how to get started building your own volume primitives. It may be useful.

http://sf.anu.edu.au/~drw900/houdini/misc/rawvol.tar.gz [sf.anu.edu.au]

With nice transfer maps you can get some great results. I use our Drishti software to build the transfer maps which I then use in vop shaders.

http://sf.anu.edu.au/Vizlab/drishti [sf.anu.edu.au]

Here are a few tests. The engine is the standard dataset, the “teapot” of the volume rendering community. The armadillo is a 994x742x732 byte value CAT scan, reasonably large. You can speed things up by compiling large volumes to I3D's and using them as 3d textures instead of using volume primitives which take for ever to read in houdini and pass out to mantra via IFD's. The HDK headers suggest that Houdini stores volumes internally as single floats so it helps to have lots of memory.

-Drew