Bifrost Liquid Density Channel -> transfer to output mesh

[brandaosa]

I have a splash effect where I can use "density" channel in arnold and render a bifrostLiquid object.

It works.

Now, I try to export a mesh (Bifrost Meshing) and the mesh itself has only bifrost_velocity and bifrost_vorticity channels. How can I transfer the channel from the bifrostLiquid object to the bifrostLiquidMesh in order to render it properly  in arnold?

I have checked this and this and this

[sepu6]

can you share the frame in question? easier to help and debug. 

[brandaosa]

the scene is quite small, so I am sharing it here.

I just can't find a way to generate mesh from bifrostLiquid and still keep the density map, so arnold would grab color information to render, as seen when render the bifrostLiquid object itself as surface (not making a second mesh object). However, I believe I need the mesh in order to generate a alembic file (and colormap info), right?

[sepu6]

This works fine through the graph. 

 

[brandaosa]

Not sure if I understood it well, but in set_geo_property_reference node you are using bifrost_velocity as Geo property, when in fact, I am looking for a way to transfer the density information from the bifrostLiquid to the Mesh. 

Left: BifrostLiquid rendered with density property via aiUserDataColor 
Right: Mesh rendereded via graph using Bifrost_velocity property

 

[sepu6]

I thought that you wanted to transfer those properties(attributes) into something to render. 

Density is fog basically when that gets converted into mesh I'm pretty sure under the hood it goes into a level set (SDF) and then into a mesh. Now I'm not sure if you can transfer that attribute from the fog density into the mesh in the old system.  If this was on the graph will be a different story, I can't help there. Since I do not use FLIP BF old system at all.  Hopefully one of the developers can help here. There might a somewhere in the many tabs something to transfer the color?

[brandaosa]

Oh, I agree the old system is very limited but I am yet not familiar with the nodes to generate viscosity or something similar to the look I am working on... the property thing would be straightforward though. I just tried something like this, but the results were far from satisfactory atm. I will see if I can somehow back irrandiace on a sequence of maps...omg 

[sepu6]

what is the FX that you are looking for? Do you have a reference? does it need to be animated or just for a style frame? 

[brandaosa]

It is just a liquid animation simulating a ring of multi-colored paint opening toward the camera. It is pretty much similar to what you can see on every image I uploaded, or, you can run the .ma file I have upload until frame 60ish. When I use emitters on a graph, and convert to volume, then back to mesh, I can't have much difference in speed between particles in a way closer particles seems connected to each other. It's more like turbulence plays a main role, but too globaly.

[thomaslisle1309 · Accepted solution]

hi. in bifrost legacy.   add the attributes like age or density to the channels list.  select the bifrost node and not the mesh node - export to .ass.  with export proceduals ticked. then import ass. and give it a aistandard with aiuserdata. in the base color channel and for the colorrset use the channel name you want ie age of density.      you might need a aicolour correct to boost the effect 

that works I did it a few days ago  cheers  

[brandaosa]

Although this is not a solution for how to transfer DENSITY channel from bifrostLiquid to its generated Mesh, it does provide an workflow to obtain a file sequence (.ass) and manipulate time what so ever.  

Also, it does not provide a mesh sequence to export to other applications. Some sorcery might be needed to generate atomic uvs for baking some texture sequence.

Could NOT GENERATE *.ASS file sequence from Maya 2023. It crashes with the simplest cube geometry as emitter.
Had to install maya 2022 and rebuild the simulation to finally export a sequence.  Is it a fact?

[thomaslisle1309]

I think there's something wrong with your computer or maya as it works fine for me!