Antoine Durr

This is quite easy, assuming you're writing out some steps to disk. Once your car animation is complete, delete all but 4 points, one from each wheel (you could use some point on the axle, or really any point if the wheels aren't turning). Write out this as a sequence to disk. This will be fast to read back in because it's only 4 points per file. Next, load back in with a file SOP followed by a trail SOP. Set the trail SOP length to $F and ‘connect as geometry’. Presto, you have your 4 tire marks. Now use a ‘measure’ SOP to measure the perimeter of these. Use a prim() function to get access to the primitive attribute, and use that in your rotation calculation.

graham
From the first script that is run you could execute a source command to manually source your other script.

It's a bit trickier than that, as you want to make sure that your environment is consistent, i.e. that all appropriate scripts get read, regardless of whether they are present. Ergo daisy chaining scripts doesn't work really well.

One solution is to write a wrapper to launch Houdini which effectively does:

houdini myFile.hip /path/to/setup.script

And then the setup.script looks at the HOUDINI_PATH, reverses the order, and then looks in each location for a 123/456 or some other named script. If it finds it, it runs it; repeat for all remaining locations in the HOUDINI_PATH.

Immediate openings for Houdini Technical Directors / Generalists who can create realistic terrains, environments and effects for a heavily science driven project for National Geographic. We are looking for one junior/mid level TD and one senior level TD through September 2011 with a possible extension into October. We are a small team working on an all CG stereo fulldome (Planetarium) show about weather on the planets and moons of the Solar System. We are based in Culver City, a few blocks form Sony Studios.

Please send resume to resumes@floqfx.com