We have been experimenting with making clouds within 3DS Max without any external plugins – we did some on our Jack Mach trailer but Chris decided to explore and play a bit further…
The first set below was using a technique we have used previously, so high poly geometry with cellular displacement maps being used as a gizmo to drive Vray Environment Fog. We have found this to be very effective for stylised clouds but as they get more realistic the render times get a lot loooonger….
Then we had a go with a new technique first presented by by Platige Image at Siggraph 2011.
The cloud is created by baking the lighting of a cloud shaped base model to it’s own vertex colour channel. Thousands of planes are then scattered all over the base geometry, randomly.
Using a projection modifier the lighting from the base model is transferred to the scattered planes.
Each plane has a radial gradient ramp with fractal noise applied to it’s opacity channel.
This produced a gorgeous painterly cloud, the problem we found with this was issues was baking the colour into the vertex channels and got a lot of crashes. Also it can be fairly limiting as you have to decide you light set-up beforehand and then bake it in. Still, worth persevering with as it does produce a lovely result…
Our third and final experiment was with using PFlow.
Using PFlow, planes are scattered across a base model again, only this time the planes are scattered throughout the volume of the mesh, rather than across the surface. Plus the planes are told to always face the camera and have cloud textures applied randomly.
The planes fake a feeling of volume and density through the use of a Vray2Sided Material. Each plane then casts a shadow on the plane behind it simulating translucency.
See below for a sample of the results. The cloud density and style can vary by altering either the maps or the particles themselves
Below are a few screenshots of the above shots being built…