rest2 in pyrosolver - what is it used for?

[pclaes]

I'm looking into the pyrosolver and working my way through the different sections, learning and trying to understand what is going on. I'm following some other papers on fluids and solvers as well to better understand the parallel between the microsolvers and the equations.

I don't fully understand how the rest2 field works in relation to the rest.

From the help file it states:

Dual Rest Fields: Creates a rest2 field that is reset in a leapfrog fashion with the main rest field, allowing one to run long sims without popping.

I see how the Gas Intermittent Solve can reset the rest fields every n frames, but where does the interpolation between the two rest fields take place - if there is interpolation at all. Or is this at shader level ?

[Mario Marengo]

I see how the Gas Intermittent Solve can reset the rest fields every n frames, but where does the interpolation between the two rest fields take place - if there is interpolation at all. Or is this at shader level ?

It's created for (and used by) the shader as a way to avoid the distortions that normally occur to any texture whose parameterization is based on the rest attribute (because the rest attribute distorts along with the rest of the fluid). The initialization of both fields (rest and rest2) is staggered in time and the shader continually interpolates between them.

See this thread for a little more information.

[pclaes]

Ahh, now I see! Thanks a lot. That info should become part of the docs - either on the shader or the pyrosolver. Or we could add it to the wiki too. Really clear explanation you did in that other thread.