topic Re: How to set particle positions using mesh_to_volume/analyze volume in Bifrost Forum

How to set particle positions using mesh_to_volume/analyze volume

richard.clarkeZMEQF — Wed, 20 Oct 2021 21:27:48 GMT

Hi,

I am trying to create a set up where particles stick and travel over a mesh. The kind of set up that would create blood trickling down and arm, for example.

I have converted a mesh_to_volume and plugged that into an analyze_volume node. I am not sure how to then move the particles to the closet point on the mesh?

Would be great to see an example.

Many Thanks
Richard

Re: How to set particle positions using mesh_to_volume/analyze volume

sepu6 — Thu, 21 Oct 2021 06:07:59 GMT

Here is a little procedural setup that you could take a little further. Basically Right now they are trails but then you could convert back the pts/trails into volumes to further process and slow down the speed as well. it could be used for rain or blood with a little more work. Right now Im just scattering pts where I have the colorset. So you could easily paint out where you want the droplet to come out.

Re: How to set particle positions using mesh_to_volume/analyze volume

sepu6 — Thu, 21 Oct 2021 06:07:49 GMT

I updated a little more the system and I added "drag" is just a dot product cheat but it works. So is little more random when the trails come down.

Re: How to set particle positions using mesh_to_volume/analyze volume

richard.clarkeZMEQF — Thu, 21 Oct 2021 10:00:50 GMT

Hi Sepu6. Thanks for sending over a set up. It looks really great!!! I opened up your .MA file and two nodes are giving errors. Scatter_Points states it has too many connections, requires 18 and is receiving 26. The Solver cannot infer a data type. Is In_P supposed to be connected?

Big Thanks in advance for your help!!!!

Re: How to set particle positions using mesh_to_volume/analyze volume

sepu6 — Thu, 21 Oct 2021 13:02:07 GMT

Hey Richard, I believe is because you might be using an old version? What BF version are you using?
I'm on the latest 2.3.1

https://area.autodesk.com/bifrost/downloads/?_ga=2.233284889.648822367.1633307953-1639519218.1607981494

Re: How to set particle positions using mesh_to_volume/analyze volume

richard.clarkeZMEQF — Thu, 21 Oct 2021 13:15:23 GMT

Ah yes. You are right. I am on version 2.2.1.3. I will get the plugin updated and have another try.

Thanks again for your help!

Re: How to set particle positions using mesh_to_volume/analyze volume

sepu6 — Thu, 21 Oct 2021 16:09:07 GMT

Ok here is the last update. This is a little different, a rain system so when the rain hits the bull or whatever you want it starts emitting the drops.
This is also to show how you can start growing your idea little by little and add more functionality.
Big thanks to Maxime for the help on this last one.

Cheers

Re: How to set particle positions using mesh_to_volume/analyze volume

yourshawm — Mon, 25 Oct 2021 19:12:52 GMT

@sepu6

I've been looking for a setup to generate drool/saliva inside of an animal's mouth, would you use this same method to do something like that? If so how would you get some of the particles to drip off of the teeth or lips instead of collecting at the bottom of the mesh.

Sorry to piggy back on this thread but this is the closest I've seen to something like that!

Re: How to set particle positions using mesh_to_volume/analyze volume

richard.clarkeZMEQF — Mon, 25 Oct 2021 19:21:19 GMT

That's a great evolution of the idea! Really cool to see how you have moved the idea on with extra functionality.

Thanks for sharing!

Re: How to set particle positions using mesh_to_volume/analyze volume

sepu6 — Mon, 25 Oct 2021 20:48:58 GMT

All good. Yeah, it can def be used for that as well with some modifications. I can probably create an example later on. You will scatter pts around where you want the saliva coming from I'll probably use MPM since BF doesn't have a flip solver yet in the graph, that would be my first choice. Mpm can do some basic "fluid" with viscosity. You probably do not want to use the project_vector node since that is the node that is keeping the pts on the mesh. Then convert to a volume and post-process that. You could also create some strands around the mouth and use the curveu attribute (it gives you an attribute from 0 to 1 per strand) to get the shape that you need and post process that as well with some volume magic.

Re: How to set particle positions using mesh_to_volume/analyze volume

yourshawm — Tue, 23 Nov 2021 18:49:21 GMT

@sepu6 thank you for the thorough description! I'll do some exploring based on that!

Re: How to set particle positions using mesh_to_volume/analyze volume

brownsa2903 — Sun, 28 May 2023 02:05:40 GMT

This is wonderful. On which node would I had a shader so that these particles render in Arnold?

Re: How to set particle positions using mesh_to_volume/analyze volume

sepu6 — Tue, 30 May 2023 01:27:13 GMT

Here

Re: How to set particle positions using mesh_to_volume/analyze volume

brownsa2903 — Tue, 30 May 2023 05:03:55 GMT

Oh thank you. would it be easy for you to update the file so that its compatible with the latest version of BiFrost? I have been looking for a rain system for about a month and its been really challenging for me as I'm primarily a character animator. Tried nParticles, Phoenix, Houdini, TyFlow and either the learning curve has been too steep for me or the results are not so great. But this really looks terrific and would like to understand it better in the latest version of Bifrost if possible.

Re: How to set particle positions using mesh_to_volume/analyze volume

ihooper — Tue, 30 May 2023 16:55:51 GMT

@brownsa2903 I think the main thing was to replace the drag node.

Re: How to set particle positions using mesh_to_volume/analyze volume

brownsa2903 — Wed, 31 May 2023 09:12:05 GMT

oh wow, thank you.

I'm still getting an error from this 1 node. any idea what I'd need to replace it with? Im on bifrost 2.7.0.1 in Maya 2024.

Re: How to set particle positions using mesh_to_volume/analyze volume

ihooper — Wed, 31 May 2023 11:59:28 GMT

It is available in the Rebel Pack:

https://area.autodesk.com/m/jonah-friedman/assets/79Cm7V1DJ

Re: How to set particle positions using mesh_to_volume/analyze volume

ihooper — Wed, 31 May 2023 12:07:26 GMT

create_particle_trails was originally a Rebel Pack node, but many Rebel Pack nodes are now being moved into the main build, so you can also try upgrading to the latest version (2.7.1.0 as of May 12)