Volumetric Clouds Poping

[tomhanks]

I used a grid to emit some particles and used a force to spread them a little, then I copied some spheres to them and converted it to volume fog and rendered, when the particles are static the clouds are ok, when they start to move it pops a lot, I couldn't make a smooth dynamic clouds moving.

I already tried to increase the resolution a lot, like 700 in a object that is the size of the home construction, the pop is a little less comparing to a resolution of 200 but not much.

I have just one light with shadow map enabled.

The problem is that I don't know what the problem is, if it is the resolution that is low or the method that I am using is not suitable for this, but all the adjustments that I did so far didn't work much.

Any tip would be appreciated, I really would like to make this work, would be a good solution for quick dynamic clouds.

Thanks.

Edited May 4, 2010 by tomhanks

[tomhanks]

I´ve changed the method that I was using, now I am using "Max Y" On the sampling and it got much better, still got a little poping, I guess I cant run away to have to increase the resolution, but I think I can get there.

Still any tips would be welcome.

[tomhanks]

Here's my first result after the modifications that I did, it's nothing realistic but what I am trying to achieve is to make the movements without pops.

The result is much better than my firsts attempts but I still got some pops, if anyone could give me some tips of how to eliminate them I appreciate.

Another thing that I would like to know is if theres a way to make the noise from the "billowy smoke" to stick to the volume like a texture so if they follow the movement of the volume.

Thanks.

clouds_01.mov

[tomhanks]

Hi, me again.

I am trying to figure out how to use the "rest" attribute to get uv coordinates to my volume for shading.

I read about it on the help of houdini but it doesn't show me how to do it when I create volumes directly on sops.

Can someone help me with that?

[TheAdmira1]

what is your life set to? often that will create popping due to particle randomly dying off and new particles birthing in at the same point? not sure if this helps, but in the past that is what create the popping for me...

[tomhanks]

Thanks for the help.

If you notice on the quicktime that I've send you are going to see that the popping start and on the general area of the clouds, Is like on frame pop on the other comes back, it's not related to the life of the particle.

But thanks anyway, if you have any more ideas it would be welcome.

[pencha]

I´ve changed the method that I was using, now I am using "Max Y" On the sampling and it got much better, still got a little poping, I guess I cant run away to have to increase the resolution, but I think I can get there.

Still any tips would be welcome.

Have you tried overriding the bounds? maybe the popping is caused by the change in resolution of the volume.

[tomhanks]

Thanks for the reply.

I did that and really made a difference but still I got some volume variation on the entire object.

[Pazuzu]

Hi!!

I can see in the video that the volume shader in not use the rest field of the sim to stick the noise, maybe that´s your variation problem.