Greenscreen, plates, and compositing oh my!

[Joe Riggs]

Hello,

My greenscreen/compositing experience is limited to pretty much talking head interviews and I was kind of thrown into this after the fact.

So there's a couple of scenes in this short, that are rather advanced for me.

1. We want this monster to climb a wall and end up on a vaulted ceiling like this http://www.finelinehomes.com/blog/wp...1/01/blog2.jpg.

The shot is static so we shot a plate of the empty ceiling and took some measurements, but what do I do on the greenscreen set? How do I have actor move, and camera positioned/angled to make this come together in the composite.


2. There's a part where a person with a flashlight comes across the monster and the monster moves toward them. So the light from the flashlight illuminates the monster.

We shot a few plates, as we were not sure which would be best, we shot one with flashlights on the background and one without.

So we have a few options on the greenscreen and I'm not sure what will be best for the composite. Just to be clear we don't see the actual flashlights in the composite, just the light from them.

1. shoot the actor with flashlights, and composite him into the plate without flashlights.
2. shoot the actor without flashlights, and composite him into the plate with flashlights.
3. shoot the actor and flashlights separately.
4. cgi the flashlights?

Any help is greatly appreciated.

[Sareesh Sudhakaran]

Without details it's almost impossible to tell but I'll give it a shot:

Use the same focal length and f-stop to shoot all the elements.

To find the right angle, distance and point of view, the simplest method is to use geometry. If that's too much trouble, try a 3D program like 3Ds Max to recreate the room's exact dimensions. Add a camera at the exact spot you shot the plate at, and then add a green screen plane surface to the areas you want the actor to move through, and rotate the whole thing till you can match that space in a sound stage or studio or wherever.

Regarding flashlights, you will have problems matching the flashlight. It's tough to visualize without any reference images. My suggestion would be to shoot the action in 'normal' light (subdued, because you'll be doing the next step). Then, use a mask in After Effects to create the flashlight beam. This is more manageable, and will match the exact angle, luminance, etc.

Hope this helps.