Best way to render cloud layers

[LT2D3D]

Hi all,

I am new to Terragen. I am working on a high profile game and am investigating using Terragen in our pipeline. Our game uses a day/night cycle, so I have no need to render skies and horizons. However, I DO want to use Terragen to create really nice cloud layers. Does anyone have experience with this process? I would like to get rid of the horizon in my renders and the best way to render out an alpha for the clouds. I tried turning off the atmosphere, which works, but I still get a black halo around my clouds. I am looking to make both panoramic, cylindrical images, as well as stereo-graphic dome images.

Any help would be appreciated

[Matt]

The black halo sounds like it might be caused by the difference between 'premultiplied' and 'non-premultiplied' alpha blending. When the clouds are rendered on a black background they should be used as if they are premultiplied images. There isn't any way to render non-premultiplied images from Terragen. You should be able to change the blending mode in the game engine. If not, you'll need to "unpremultiply" the RGB first.

Matt

[jorxster]

Hey LT2D3D,
I'm in the same boat as you. been learning and rendering clouds with Terragen2 all week in hopes of creating elements for a matte painter, cyclorama, etc.
Switching off the atmosphere is key, as you've already found.
What software are you loading up the renders?
If I load up the colour and alpha in Nuke, and merge over another plate, it merges perfectly, as Nuke assumes the render is premultiplied by default. If you're getting black edges, like Matt says, you may need to unpremultiply the image. (divide the rgb by alpha).
cheers,
Jordan