Hi everyone, i have a very small problem…I'm trying to get a vehicle to follow a curve on a very bumpy surface….i have the vehicle to follow the path fine, but i want the path to accurately represent the bumpiness of the ground. Is there a way of like projecting the curve onto the surface? If so, what exactly do i have to do to do it? I'm thinking some sort of resampling to increase the number of points on the curve, but what next…?

Thanks for the help!!

Yeah, resample the curve using the Resample SOP and then use a Ray SOP to project your curve onto the surface.

Thanks for the quick reply…i've done that, but it doesn't seem to work over the areas of the ground where i have pushed the ground DOWN using the sculpt SOP. It seems to work fine over the rest of the surface, but… I've tried playing around with the resampling parameters, cos i thought it was due to there not being enough points, but it doesn't seem to make any effect.

It may be overkill for what you want, but Renato Tarabella has a great example file on his site that may give you a few ideas - http://www.tarabella.it/Houdini/Houdini.html [tarabella.it]

PenguinOfDeath
Thanks for the quick reply…i've done that, but it doesn't seem to work over the areas of the ground where i have pushed the ground DOWN using the sculpt SOP. It seems to work fine over the rest of the surface, but… I've tried playing around with the resampling parameters, cos i thought it was due to there not being enough points, but it doesn't seem to make any effect.

Add a facet sop to your line and turn on precompute normals. This will show you the direction in which the rays will be projected. You then need to move your line in the opposite direction until it is completely above or below the surface you are raying onto. If some parts are above and some below the rays will miss some parts.
Alternatively try turning on ray by minimum distance rather than projected.

Sorted..cheers guys.