Fri, October 21, 2005
Image-Based Lighting—11:49 AM
A quickie: one thing we learned in class last night was the concept of image-based lighting. Basically, you apply an image (for example, a photograph of an environment) onto the inside of a big sphere that surrounds your scene. Think of a planetarium, with the stars projected all over the ceiling. Then you render the scene with that as your light source, and it's a quick way to place your rendered objects in an environment with similar lighting properties.
(By the way, I'm committed to a time when onebee is more than just Survivor and 3D graphics. But I do not know when that time will be.)
On a high-budget special effects movie, this photograph would be generated by taking a picture of a mirror ball, which allows the camera to capture a full 360-degree panorama in one shot, which can then be extracted with software to create the surrounding lighting environment. We just use a single picture and hope for the best.
Fiddling around with this, I got very lucky with a snapshot I took this morning in the corner of my office. (Next week's homework assignment is a car tire and rim – we worked on the rim last night which is what you see below.)
I'm particularly pleased with the backlight effect from the window. This is just dumb luck – you can see that the desk lamp doesn't really show up as part of the illumination; I think it's too small in relation to the total size of the scene. Clearly, some photographs lend themselves to image-based lighting better than others. I think my interest in 3D is going to be character animation, not compositing with live action footage. Otherwise I'd just invest in a mirror ball.
