Three Pass Greenscreen

taylormade

taylormade

Well-known member
I managed to shoot a greenscreen sequence with the green screen too damn bright. I'm having a very tough time getting a good key and need some help. I've been trying to use the 3-pass method described in Mark Christiansen's book Visual Effects and Compositing Studio Techniques. I'm obviously doing something wrong. Has anyone out their used this method and if so could you take me through it a step at a time? I know you need a garbage layer a core and and an edge layer but iIcan't seem to make it work. I keep ending up with a blank screen. I'm confused if each layer is a Precomp or not and the correct layer mode for each. Can anyone help?
RT
 
I would literally have to write a five page paper to describe the final solution to my problem. Basically, I didn't need a garbage matte since my actors were in a car and the greenscreen was totally even - but overexposed. I made a precomp core matte, shrinking the
edges and blurring it slightly, then made another precomp that concentrated on the hair and layed that over the core. That precomp was too thin for everything but the edge of the hair, so the core below kept things solid in the middle of the key. I had to do some masking when the woman's profile showed up against the night sky, so I made another layer with the Keylight set for her profile (too clipped for the hair) and used maskes to hold out just that part of the frame. I also discovered that I had forgotten to use the premultiply feature on the hair and that got rid of the white fringing. A lot of work for a six second scene, but it works fine now.
 
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