Hey Guys, I have a deadline coming up and I can´t find the specific information on the following questions.
Iám quite new to houdini, so I´m sorry if its too basic.

I´m using the pyro solver just for smoke and working with billowy smoke shelf version as a startin point. Emiiting the smoke from a moveing/flying object, I want thick smoke hitting the ground, spreading a little bit and vanishing.
My Smoke is emitting properly and falling down, but here are a few (maybe simple questions):
- How can I collide the smoke with my groundplane (Grid), just seems to work with a thick box -> collide with object shelf function used

- My resize container is expanding without limits, cause of the moving object. How do i give the smoke a duration. Where do I control when it vanishes?

- Upres. Is it obsolete in H13? I found a few posts on that. Should I just cache with low div size?

- Shading: What Parameters do I have to keep in mind and how do I preview it properly?

I KNOW, its a lot. But its my first smoke sim and I want to use Houdini for it. Complicated at first, but just great. :wink:

About Collisions , when you use one side objects such as simple grid , you should make double side them to achieve thickness , you can do that with Volume Extrude SOP , Extrude SOP or PolyExtrude SOP , But if your grid is useful for Ground , You can use Terrain Object instead of Static Object in the Shelf , It make thickness for your grid automatically .

About Resize question , yes , if your object is moving and your smoke emitting from this object , your container should be expanding until tip of the smoke die !

So you can control this resizing by changing lifespan of the Smoke , for doing this you can increase Dissipation parameter in the Pyro Solver -> Shape .

Also for fast moving objects you should increase Padding in the Resize node or even turn off Clamp to Maximum parameter and in some different situations you should increase SubSteps too .

About Upress , Yes your can save your lowres simulations to the disk , then use these cache's files for upress , But I suggest you to save your simulations to the disk as *.bgeo files instead of saving *.sim files (via Explicit Cache). in this case you can compress your volume to achieve very small size on the disk , because large volume's file are so big on the disk.


And some different things are useful for rendering good pyro such as :
1.Using Raytrace Shadows
2.Using Raytracing Rendering Engine
3.Increase Transparent Samples for Stochastic Transparency in the Mantra node

About Shading I usually use Flames material (in the Material Palette window ) , It has too many controls for rendering Pyros .

Great!!! Exactly what I wanted. Thanks so much Joker!!!

Just one question left. When I save my sim to disk as bgeo I use full resolution, lets say 0.02 div size?

EDIT: Just did a little rendering, looks good except the smoke looks a bit “edgy” you see the square volumes it is built of. You happen to know how i get rid of these?

skywalker_ll
Great!!! Exactly what I wanted. Thanks so much Joker!!!

Just one question left. When I save my sim to disk as bgeo I use full resolution, lets say 0.02 div size?

EDIT: Just did a little rendering, looks good except the smoke looks a bit “edgy” you see the square volumes it is built of. You happen to know how i get rid of these?

Yes , that's good . I usually use single Solver with perfectly division size instead of using Upres method .

Also you can take better result with increasing Turbulence and decreasing Swirl Size in the Pyro Solver–> Shape .

To prevent “edgy” result you should decrease density field in the material , if you used Flame material , you should just decrease Final Amplitude in the Smoke->density .

ok, turns out the Volume Filter was the problem.

Thanks again for everything, you really helped me out here!