I figured out a way to create a fake "multilight" video using the output of any render program. All you need to do is:
- Render one image per light source. You can simplify this part by hiding all lights except one in each scene, and then batch rendering all scenes (with the same camera, of course). If your render plug-in offers different model update modes for animation, be sure to select "update all". For best results, set all artificial lights to white and tone them down a bit to avoid burned out parts in the rendered images.
- Open all renders in your photo editor as layers, and switch blend mode to all of them to "addition". Place a black background at the bottom of the layer stack.
- Start your screen capture program, and start recording the image area, while you play around turning layers on/off and adjusting the opacity and the color of each one. Make sure to create shortcuts beforehand in your photo editor for some basic tricks you'll be using so no drop-down menus appear in the final video.
- Post to Youtube.
- Give your cat a tasty treat for not chewing your computer cables while you were doing all this.
Here's my humble attempt with Twilight Render + GIMP (free) + CamStudio (free, too):
http://www.youtube.com/watch?v=yLODhLdDJnI
Now that I stop to think about it, you could also use this method to generate infinite still images with different colors / intensity for each light source without having to re-render, no matter what render plug-in you're currently using. Yes, I know some have this already built-in, this trick is for the rest.
