[SOLVED (sort of)] Threshold issue when converting to SDF

[iamyog]

Hi

 

I'd like to reshape a volume in a volumeVOP by using SDF informations.

While it works properly on a static volume, I'm facing a problem with something evolving through time : please have a look at the attached file, my input is a simple smoke sim.

I can't find a way to compute the SDF information right inside the smoke solver (the only gas microsolver are for Geometry or particles) so I tried to convert the "DOP imported" sim.
Problem is that either via VDB or standard volumes, I obviously need to specify an IsoValue that define what's inside or outside. I suspect this threshold to be the cause of some flickering when I convert that back to normal fog.

Just flipbook a few frames on my example file, you'll quickly understand what I mean : the low density edges are flickering. It is indeed visible afterwards in my reshaping and at render time. I know I can reshape by using the density only but I'd like to use the SDF.

 

Is there any way to prevent this behaviour ? or maybe there's a simple way to output SDF values from the solver itself.

 

Thanks

smoke_to_sdf.hip

Edited February 12, 2015 by iamyog

[iamyog]

I found a way to minimize that by taking several samples at different IsoValue and blend them together after.

I'm unsure about how much sharp details I'm losing due to this, but the problem is smoothed out.