I am trying to make a group of particles follow an irregular surface in the POP editor, but would like to apply other forces to the particles as well. As far as I can tell, once you apply a creep POP, the others are overridden, and no other influences have any effect. Is there a way to make this happen, or does anyone have an alternative method for me to accomplish this?

Thanks

In Houdini 6, there is a new addition to a particles state; slide. When particles are sliding, they take in to account all the forces in the scene. You can blow the particles right off if you want. Use the collision POP to initiate the sliding as it is the easiest way to start the effect.

Thanks for the solution using Houdini 6. Unfortunately, I'm using 5.5. If anyone has a solution using 5.5, it would be much appreciated.

You can use a creep SOP to creep your source along the surface or slightly above and thus can apply new forces to your particles.

What if you want the particles to slide on the surface but be emitted from another peice of geometry, say a grid llocated above the surface you want the particles to slide along or over? I have been meddling about with particle sops lately and haven't found a solution I really like for this kind of behavior, am I better off working in POPs than trying to do it in SOPs?

Any thoughts from the Houdini particle guru contingent? I am a little new to Houdini particles and find the SOP/POP thing a little puzzling at times. I suppose it is just a matter of getting used to a different workflow.

Cheers,

Anne.

use your grid above the surface as an emitter and apply a negative force (gravity) to your particles. then use a collision pop and select your surface as collision geometry, within the collision pop you can specify that the particles slide.
I'm not near Houdini at the moment, so can't set up a sample scene.

No worries, I will try that out, thanks for the response.

Cheers!