Hello,

I ‘am making test with colored smoke. Regarding example shared by Peter Claes, I made a smoke setup where the goal is to transfert color informations of source ( points) to the smoke’s voxels and advect theses colors by the velocity attribute.
My problem is the colors doesn't advect and mix correctly. After some frames appears color loss and artefacts.

How could you improve my system ?

Thanks for your help

Vincent

Some thoughts after a quick look
- The streaking artefacts come from differing Cd and density volume extents, add Cd (and CdFuel?) to Extra Resize Fields in you Gas Resize node
- The particle to volume settings don't necessarily match between CdFuel (done in SOPs) and density (done in DOPs), so there might be some less-colored density created
- Some of the color loss might be due to opengl preview..
- The differently coloured smoke parcels will unavoidably mix as the simulation advances. You can probably mitigate that by using more substeps, and maybe by using a higher order Advection Method (HJWENO?). Remember to use the same method in your color advect node as you use in the smoke solver.

This all would need quite a bit of testing to see if it actually helps, so take it with a grain of salt

thanks for your answer.
I will sutdy that point by point.
The other thing is I am not aware about advection theory. I am no sure to get the difference between the advection type and advection method …

ps: other question about my particle to volume setup. Why dop you say my Density is done in DOP ?

vbk!!!
ps: other question about my particle to volume setup. Why dop you say my Density is done in DOP ?

The density volume sourcing is done in part_to_density Gas Particle To Field DOP, while the Cd sourcing (CdFuel) is done in volumefromattrib1 SOP.

Adding Cd and Cdfuel in the extra fields of the GasResize make the thing comes better !

I will test a few more things based on your advices.

Thanks again.