CG Taiwaner 台灣人玩動畫: Phoenix FD Tutorial: Large Scale Smoke

2011/03/17

Phoenix FD Tutorial: Large Scale Smoke

Tutorial results

Large scale smoke with Phoenix FD 03 (1920X1080 HD video)

Large scale smoke with Phoenix FD 04 (1920X1080 HD video)

This continue my previous two tutorial: explosion, nuke cloud. Please read those tutorials first if you are not familiar Phoenix FD.

Though this tutorial is for advanced user, it actually no much different than previous tutorials. We will show you some tips/tricks when creating large scale smoke with PhoenixFD.

First of all, upgrade your OS to 64-bit Windows 7 and get as much memory (RAM) as possible. Since large scale smoke means lot of cache generate during simulation. So if you want to create high detailed smoke like this, be sure to get a powerful machine, total 8GB system RAM at least.

Scene setup:

The main different than previous tutorial is, we have a 3dsmax std gravity force here, point to left to make our smoke moving from left to right. Otherwise, the smoke will moving upward.

For the PHXSource, we want to it emit smoke continuously, so set the discharge to 100, temp to 2000 and smoke to 10. Add the plane as source.

For the dynamic simulation part. Quality, Maximum step and cell size---those there parameters are the must important. Set cell size as lower as possible (if you have enough system memory), here I use 0.6 cell size, this will generate roughly 5GB of cache after total 300 frames simulation. The default Maximum step is 8 which is not enough to generate detail. I set it to 30.

Uncheck the std Gravity. This will force the simulation system to use other force in the scene (you should create a Gravity point to left in the scene, strength=1)

Sampler type the Truc, this will force it to render each voxel withous bluring it

Image above showing when not using enough Maximum step (=8) will generate bad resuls.

For the Colors and Transparency, change the color to dark gray. Set the Multiplier to 2 (enhance the light scattering effect)

For the target Direct Light, make shadow a VRayShadow. Multiplier to 5 and color to orange to mimic sun color/intensity. Check the Atmosphere Shadows.

Finally, for the rendering setup, set Vray as screenshots above. Do not set the Irradiance Map presets too high, since we set the Sampler to Truc which will render each voxels, too high sampling will render voxel over sharp.