I'm trying to use a flip sim field to effect a pyro sim field (fuel). I want to use the FLIP particles to locally remove the fuel for the pyro sim. In SOP level this would be straightforward with an attribute transfer node, but in DOPs it's not quite clear to me yet.

I'm using an Apply Data and Fetch Data to get a field from the FLIP sim, which at the moment is just the viscosity (because it is a scalar = 0). And then a Gas Calculate to transfer it to the fuel field on the pyro sim. Unfortunately it seems to just replace the whole field rather than just where the particles are close to the fuel source.

I guess I just need a way to make the transfer local to the particles. I tried adding “Geometry” to the Source Index on the Gas Calculate node, hoping it would be able to use the FLIP particles as reference points for transfer, but this didn't work.

I have a test scene attached. Just switch the Gas Calculate on…

Maybe you can try using the surface field from FLIP. Since it's a SDF, you probably don't want to add it directly. If you set Source Conversion to SDF to Fog, then you can subtract it from Pyro's fuel. See the attached hip file.

You can fetch the particles and transfer a attribute with the particles to field DOP.
I created a cooling attribute on the particles and used it to subtract from the fuel field.