Title says it all really…
I’m wondering if it’s possible to use the wetmap created from a water simulation in a second simulation (smoke being emitted from the wetmap).
If so, how might I go about doing this?
Many thanks.
Hey,
Yes you can do that. You can use a Phoenix Particle Texture and pick the Wetmap particle system. You can find more about the Particle Texture here - Phoenix for 3ds Max
Then just use this texture as a discharge mask in the Fire source you wish to use and it should work. You might need to adjust the Particle area radius in the Particle Texture settings in order to avoid some spottiness.
Oh, that’s excellent. Thank you for the super fast reply and informative answer.
I guess I still need an object that emits, correct? I can’t use only the texture?
Yes, you will need to have an emitter object 
Just pick the one that is covered with the wetmap particles.
So is this a case of creating a Fire Grid basically the same size as the fluid grid and then somewhere in there using the wetmap particle event from the fluid system as the emitter? Sounds pretty straightforward, which means whenever I am doing something it is not that straightforward
Oh, there’s no need for the grid to be the same size. The wetmap particles are exposed as a standard 3ds Max particle system, so you can just pick them and emit from them.
However! For the wetmap to appear in the Liquid simulation, the geometry over which it appears must be Solid. If this geometry participates in the Fire/Smoke sim as well, then it’s possible that it gets voxelized over the wetmap, covering it and preventing it from emitting.
If this is the case in your scene, either exclude the geometry from the Interaction rollout, or if you need it to be solid for the Fire/Smoke sim, them go to the right-click Phoenix properties of the geometry and set Voxel Mode Override to “Inscribed”. This way the voxels of the obstacle will contract back 1 voxel and the wetmap will be free to act in the fire/smoke simulator as well.
Just in case, make sure the Fire/Smoke simulator excludes the Liquid simulator, and excludes the liquid Source as well
Hope this helps, cheers!
For reference, I made a tutorial on how to work with the wet-map (as an emitter, in conjunction with a water sim), maybe it’s helpful to someone in the future: