Less detail...(!)

[gardeler]

Hello
I have been using PhoenixFD for a couple of months now, and I have 2 questions:

1. I'm doing a fire simulation with a large smoke trail. To get nice flames of fire, the resolution of the grid is pretty high. This is causing the smoke to get super detailed. (which is something that is usually what you would want), but I have been asked to reduce the details in the smoke and make it softer. And that turend out to be kind of difficult! I have tried a few different things, like switching to "smooth" instead of "classic" but but the result looked wierd. (but softer)

Is there any way of achieving softer or "lowres" smoke without breaking up smoke and fire into separate containers? (It takes much longer to render in my tests.) Best case would be to solve this in rendering, or a post process if possible. (I only have fire and smoke channels though)



Next problem

2. I'm having a hard time to get the smoke to spread out and dispurse as it rises. It looks more like it fades off over time, and the shape gets too pointy at the top. The goal is to get it to be more funnel shaped. I'm using a turbulence field for adding movement, but the smoke seems to have only little or no outward motion, and more upward. (the up speed is good, just need more out.)

I'm currently using v2.2, so if there are anything in the nightly's that you think would help, let me know.

Thanks

M

[Svetlin.Nikolov]

Hey,

You could smooth out the simulation at render time using the Frame Smoothing in the Input panel - it was originally designed to remove grid artifacts from liquid meshes, but it will work for smoke as well

The pointy shape is an issue that is fixed in the nightly builds, but I'm not sure what you can use to make the smoke spread more..

[gardeler]

Thank you for the fast reply! We are using the volumeGrid for rendering in vray for maya. Is there an equivalent feature in the volumeGrid?

...and would this not affect the fire as well?

Cheers!

[Svetlin.Nikolov]

Unfortunately the smoothing is not yet added to the Mayan Volume Grid. If you get a latest Phoenix nightly for Maya, then you will get all the stuff that's been added to the Volume Grid since the last Phoenix release - they share the same code.

There will be no effect on the fire, yes - you can choose which channels are getting smoothed independently from one another.

[gardeler]

That sounds awesome!!! (except that I do not have access to maya phoenix nightly's) I will ask for access.

Thank you Svetlin!

[Svetlin.Nikolov]

Good luck!

[gardeler]

By the way, what is the plan with volumeGrid vs the phoenix shader? As you point out it is the same code. Will one replace the other? Or is there something new coming?

[Svetlin.Nikolov]

Hey,

They are basically one and the same - each new version of V-Ray or Phoenix snapshots the current state of the Phoenix grid shader and anything we add will be immediately visible in both products' nightlies. Currently we plan on both coexisting together so you can load foreign caches into V-Ray more easily

Cheers!

[gardeler]

Sounds really good, but the parameters ar quite different between the two, even if the code is the same. If you would want to use temperature as transparency, it is very difficult using the volume grid as it uses normalized maya ramps. (0-1) In my tests I had problems getting it to behave well. That was much easier using phoenix shader as it has it's own ramps / curves, so you don't need to try to force the values into the 0-1 space. Will you create something similar for the volumegrid node?

[Svetlin.Nikolov]

Absolutely - the Mayan VolumeGrid needs some more love user-interface-wise. It's the only place out the four Phoenixes/VolumeGrids where we still have the old ramps. Hopefully soon this will change.

[gardeler]

Thanks for letting me know. This is actually the only reason that I use Max. (we are a maya based studio.) Many of the max plugins are available for maya too these days, but maya is always the last platform to be updated, so I preffer to stay on the "native" software of the plugin, even if transferring data around is a pain.