Animated Cd affecting and sticking to FLIP particles

   4049   5   1
User Avatar
Member
32 posts
Joined: Dec. 2014
Offline
Hi Guys,

Wondering if I can somehow have an animated noise map affect my FLIP sim then once that happens the FLIP particles can inherit that new color also for their remaining life. In the attached file you can see I've got the color being read in via a sop solver but of course that color doesn't follow along with the particles once it's been read in. Any help would be great, very new to Houdini here

Cheers,

Ben.

Attachments:
angel FLIP.zip (849.1 KB)

Kind Regards,

Ben
User Avatar
Staff
763 posts
Joined: July 2006
Offline
Your setup was very close. The problem is that the FLIP particles are moving through space and picking up whatever color is currently closest from the animated noise map, so the colors don't track with the particles.

There's a few ways to fix this:

Since you have Reseeding off, the easiest way in this case is use an Attrib Copy rather than Attrib Transfer. The former just copies color directly from the source geometry by matching point numbers, and in this case you've got a one-to-one mapping.

A more generic approach (e.g. supports reseeding or other color sources) keeps the Attrib Transfer but first applies a Rest Position SOP to the original particles, creating a “rest” attribute with their original positions. Then in your SOP Solver move each particle back to its rest position before doing the AttribTransfer, then Attrib Copy to the particles in their current positions in the simulation.

Or you could do the whole thing in one AttribWrangle using point clouds.

The attached shows each approach.

Attachments:
angel_FLIP_rest.hiplc (1.6 MB)

User Avatar
Member
32 posts
Joined: Dec. 2014
Offline
Wow Johner,

Thank you so much dude, I was super close to the attrib copy method you've shown here. Had no idea what the difference was

I appreciate you showing me multiple methods also, the wrangle stuff looks great, a bit over my head at this stage but I'll definitely try to start using them in my setup's.

You're a champ
Kind Regards,

Ben
User Avatar
Member
2624 posts
Joined: Aug. 2006
Offline
Edit to johner's post . I would approach it slightly different

I would create a trigger attribute in sop land. Cd.r = f@mytrigger , then feed that into dops. Then for example create a force pop and use a vex if statement to drive the effect

if (@mytrigger >= 1){
    @Cd = {0,0,1};
}


I would also strip down your scene to the bare basics to prototype ideas !. You can also maybe have a hunt on my website . www.circusmonkey.com.au for a whole ton of vop sop examples. They should give you a few ideas. do remember though that in H14 theres a lot of workflow changes to attributes with vex now the driving force.

Rob
Gone fishing
User Avatar
Member
2624 posts
Joined: Aug. 2006
Offline
Email me off list

Rob
Gone fishing
User Avatar
Member
43 posts
Joined: May 2013
Offline
I just wanted to say thanks for the file angel_FLIP_rest.hiplc! That's a great succinct example of a rest position setup.
  • Quick Links