Dust - various doubts

[traiano]

Hey everyone,

It turns out that Im working on a dust simulation from fractured rigid bodies.

This simulation has 1.4 Divisions and before I enhance the Divisions to cache again the final sequence, I want to fix this problems Im having.

Im using Whispy smoke shader. In the light blue square, the smoke seems to have dots inside, like a net. Why is this happening?

In the red circle, there is a pretty flat end of the dust, how can I make this simulation more like a ball while the tip goes down?

Im ok with the yellow circle, I like to see the rigid bodies through the dust, even though how can I set more density in the smoke so that the early smoke lose density and the new one has a lot of it?

Trai

[rafaelfs]

Hey,

The flat end of your smoke container could be due to a re-size issue, you might have to fiddle around with it a bit by adding some padding there (I'm assuming your pyro setup has a gas resize fluid dynamic microsolver attached to it...)

Now to change the density of your smoke over time, you might want to turn on/up the dissipation in your pyro solver, in the shape tab.

Cheers

[fayal]

hi,

Martin i think ,

-first problem is due to resize fluid or cache memory try to play simulation in flipbook with desactivate cache simulation in DOP.

-second problem may be its due to Buoyancy force make your Buoyancy Dir in pyro solver 0 -1 0 and ply with the Buoyancy lift.

verify also your velocity direction you can change it in SOP.

-third problem i think there is many ways sure you need activate the dissipation and play with it,

play with scale source volume in DOP source volume .

-paint density in your source emitter smoke in SOP.

hope this will help but maybe if you share your file will be best.

[traiano]

Hey guys

thanks for your indications.

I resolved the issues by re caching with more divisions, enlarging the padding for the flat bottom, the dissipation, setting different density and noise at the shader. Then rendering with better quality and volume step size as 0.04

[traiano]

How is it possible to generate Trails in dust?

Is there any way to add something like here represented in yellow to my existing smoke cache or if i cache a new simulation which parameter increase trails and lost smoke?

[LouisXIV]

Have you tried adding additional particles/debris as a source for the trails?

[fayal]

may be this topic will help

[traiano]

Have you tried adding additional particles/debris as a source for the trails?

No, actually thats a great Idea, I will try it

[traiano]

Faicel. I will try this thanks

First check your Pscale attribute in SOP .It can be too big by default.

Second check your Gas Particle to Field microsolver --> Max Extrapolation Cells by default it 2 but it depends on voxel size.

Third check your vel attribute if you use it.

[JuriBryan]

for the trails:

delete out your hero pieces from your RBD sim, or simply the pieces that should have a trail.

Then use them am a source for a new pyro simulation.

I would go with the exact same set up that you had for your base sim (simply plug in the new source) and then play with the dissipation settings to make the smoke last longer.

Also apply a damp node to make it "sick" a bit more.

And if you want to go a bit more crazy in the details with it, I would add a VOP force right before the gravity node.

In there check the vel of the smoke, and if it is bigger then 1(or what ever looks best) apply a curl noise to the existing vel of your sim(simply add them together) you can also put in some ramps and multiply them with the curl noise to control where and when it should be added to the sim.

That should give you some nice trail effect.

As for the rendering, render them on a separate layer/pass with all the RBD pieces as masks and use the same shader as for the rest of the smoke.

and then comp them together afterwards. that way you can change the color of them in post and make them stand out a bit more with out looking like they have a different material as source.

Hope that helps

[traiano]

Hi Jury, thanks for your input, I did what you say and things are getting better in this new dust simulation.

How is it possible to divide a shader in 2 colors+alpha based on AGE? I want new dust 'lighter´ than the old one.

How to add a texture on a broken face piece?