Hello!

Can someone please explain to me, or point me to somewhere where I can read in layman's terms why my density field is less and less dense when I put more substeps?

I've quiet rapidly expanding sim and was trying to get better quality using more substeping - however when I add more and more substeps the density is lower and lower. This impacts the look and feel of my sim quiet dramatically.

After suggestions on Discord I've tried to change the substeps on DOP net rather than Pyro solver but the result is still less dense.



This is the result using 1/1 substeps in Pyro/DOP Net



This is the result using 1/3 substeps in Pyro Solver



And finally using substeps on DOP Net rather than Pyro

Is there any other place I should change the substeps? Why is this happening? I've searched a bit and I think it is because of the interpolation between voxels but how do I counter that? Just add more density into the volume? Doesn't sound like a perfect solution - I'm working with low res/low substeps for fast iterations - adding more substeps changing the look of my sim seems a bit too unpredictable.

Any help would be appreciated.

I noticed in one of your images a gas dissipate DOP. If I were to guess this DOP is being run on every substep. So if you go from one substep to 3 the gas dissipate DOP will be run 3 times. So there will be less density. I believe the dispate in the solver takes substep into account. If you crack open the solver and take a look for the gas dispate DOP it should give you an idea of how to do it yourself. Can't check at the moment as I don't Houdini in front of me.

PS In future try posting a hip file it makes diagnosing the problem a lot easier.

Thank you for your answer.

I did try to follow your suggestion by disabling dissipate microsolver and enabling the one on the Pyro Solver itself. The results however are still less dense when on higher substep count. I also checked out how this Pyro Solver looks inside and I must say - this is a bit too much for now.

This time I'm including hip file