Maya - Cartoon Clouds - Any Ideas?


I feel like a lot of this look could be achieved with shader tricks. A kind of fuzzy opacity falloff based on facing ratio (assuming you don’t have overly complex, concave/convex shapes), and some hacks to the ambient based on the illumination. Use SSS if you want to fake the scattering inside the cloud a bit.

It wouldn’t be quite the same quality, but would that work for you?


I would use cards, and for “hero” clouds use fluids. You can paint the clouds to be “lit” correctly in each scene, which would take a little time, not much considering how simple they are.

  • Needs to be affected by lighting so it can be incorperated into various environments.

See above

  • Needs to render in a decent amount of time.

Cards render quick. And clouds aren’t generally the focus of shots.

  • Needs to hold up at a very large scale.

If you paint it large it will work.

  • Needs to cast shadows on environment.

Flip the card 90 degrees, turn off primary vis…instant shadow creator.:slight_smile:

Hope that helps. If not, sorry.


Bonedaddy - The opacity trick sounds pretty cool I’m going to give that a try. Will using the facing ratio always guarentee the opacity will be affecting the edge? It would definitely give me 100% control over the shape of the could. Unfortunately I don’t think I can afford to use any SSS shaders this time aroud.

Remi - Your suggestion about using the cards is great I never thought to flip them to create the ground shadow. Now in regards to the hero cloud I can’t seem to get fluids to work on this massive scale( I had nothing to do with the scale). Unless there is some way to blur them a lot to hide the jagged voxels or just a way to make the resolution work…I’m trying to prevent any post work if possible.


Ok, I managed to get the facing ratio and the opacity map working correctly and it is working pretty good. It needs to be tested in a few shots though to see how well it fits in with everything else. I will keep everyone posted on the results please feel free to make any other suggestions though as I would love to try some other options.


Here is a very funky technique that might work for you.

  1. Select your cloud mesh and do “EditMesh: Transform Component”.
  2. Create the following expression on the resulting polyMoveVertex:
    float $edgeBlur = 0.2; // set to the desired amount of edge softness (negative will blur inward)
    polyMoveVertex1.localTranslateZ = $edgeBlur * (frame %2);
  3. On the camera set shutterAngle to 360
  4. Render in Mental with motionBlur = full deformation. Lower the mblur time contrast for a smoother render.

This can create a really nice soft look to the shading. Basically the object is vibrating along its normal at the frame rate, so it uniformly blurs. I’ve not experimented, although it could look strange in some cases, like when the camera moves quickly.



Duncan - Very cool method to get the edges blured. I’ve already ran into a little glitch with it so far, I tried animating the object and the size changes every other frame. I will continue to play with it a bit more and see what happens with it though. Thanks for the suggestion you always have great advice on these forums.


The object should jump back and forth in size each frame in the viewports, but the rendered version should look smooth as long as the shutter angle is 360 and one has motion blur on.

However when one animates motion of the object one can tell that it is vibrating (in the render), as the subtle changes in motionblur are the clue the eye needs… ah well.



Wow Dunkan
You are great :slight_smile:


For the kind of look you’re after, low detail fluids should actually work for you. They’ll render fast enough if you crank up the shading quality and blur the hell out of it. It would still give you a good volume and shading.


could it be sculpted?


Fluids could be emitted into roughly modeled poly clouds and that would allow you to art direct basically any shape you want. I’m not too proficient with fluid sculpting itself so I’d prefer hand modeling my emitter objects this way.


Wow, that is some seriously lateral thinking.




A similar cheaty-cheat-cheat is to use clusters/deformers/blah to deform the surface, write it out as a .mi with motion blur info, and read it back in as a proxy. If you render with the rasterizer you’ll get basically a bullet time frozen-moment motion blur effect that renders very quickly. Stumbled across this while doing RnD for a project I’m working on now, must exploit this in future…

You can’t just go file->export->proxy unfortunately, as it doesn’t take motion into account. You need to export your object with the Mayatomr command, then wrap it in the bounding box/assembly info. Fiddly, but works. More details over on the mental images forum:



reminds me of LWs spinning light/motion blur tricks! :wink:

lol who woulda thought in Maya?!


Damn. That response just slayed whatever thoughts I had on approaching this… Way too early in the morning to read that :slight_smile: … Reminds me of the ol’ LW trick of jittering a light on the in-between frames to fake that soft shadowy look!


I have a thread on this in the Maya Rendering section.

We’re using nParticles to fill a polygon cage (this is roughly how pixar made partly cloudy). It’s awesome. Render times need to be optimised (i got the time down from 80mins to about 5mins just by lowering the fluid shading quality) but it’s a good start.


I would think particles emitted from and goaled to the surface would be quicker to render than a mesh filled with particles.


I’m not very knowledgeable about vfx in Maya, but what about alternatively getting the softness effect in Post? You can just crank out an AO pass on whatever cloud shape you want, and then in PS run a macro through the frames to blur / opacity / glow to the desired levels. Would be a quick render and allows you full control over the cloud shapes.


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