I’m new so sorry if it’s a stupid question but the title says it.
A composite is a mixture of things. In the case of films (and TV for that matter), Compositing is basically mixing, say, live action and CGI or mixing 2D photos and 3D models. The result is anything that has “special effects” in it.
In addition to using compositing to add 3D elements into live action shots, you can use compositing to separately render the different aspects of a 3D models materials, such as specularity, reflection, and shadows. You can quickly make adjustments just by changing the opacity of the various layers, as opposed to having to re-render the entire scene.
In the pic below I started with the photograph of the trees. I rendered a diffusion pass of the AT-ST with no shadows. I rendered a mask pass to separate the diffusion pass from its background.
Then I did two shadow passes, one was fairly diffuse and the other had more direct lighting. When compositing, both shadow passes are set to Subtract or Multiply. You can easily control the lighting by adjusting the opacity of these shadow layers. In final image below, the AT is a bit too dark so I could just reduce the opacity of the Shadow 1 layer.
I could have also rendered specularity and reflection passes. These would be done against a black background and the layers would have been set to Add. The laser blast layers are also set to Add.
For still shots I composite in Corel PhotoPaint. For video I use Corel Lumiere, which unfortunately isn’t available anymore.
Steve S.
That’s a nice visual example, Steve. Did you use 2.43rc2 to render out in passes? I’ve really got to figure out how that works.
I’m using 2.42a. I just rendered everything separately, basically because that’s the only way I could do it when I used to use Bryce. I haven’t really looked into whether Blender allows you to render all these separate channels at once.
For the diffusion pass I turn up the material’s Emit slider all the way to eliminate any shadows. You don’t even need any lights for this pass. This pass renders very quickly.
To do the shadow passes, I just paint the model pure white (no textures) and render it against a white background. For specularity passes, paint the model black and render against a black background. To do the mask, I eliminated all the lights and rendered the model (which appears black due to being unlit) against a white background. (It’s been inverted in the example above.)
Steve S.
That’s a creative way to do it, indeed. I think the next release will simplify things for everybody.
Thanks, that looks interesting. I’ll have to look into it. It should save quite a bit of time.
Steve S.