by Jack needham on Apr 15, 2011 at 10:51:49 pm
I've recently started using Voodoo to motion track and it turned out quite well, but as you can see from the youtube video below, it doesnt look at all realistic. How do I export with shadows etc from 3ds max? Thank you. :)
Re: Motion tracking by Ryan John on Apr 17, 2011 at 6:00:42 pm
Tracking is rarely about putting an object into an environment but replicating a scene to match an environment, it is all about observational skills.
Before you insert visible objects its best to build what you cant see. Start with the desk surface, a simple box should do, then gradually build up the other objects in the scene with relatively primitive objects, use boxes, cylinders, planes to make the keyboard, glass, monitor, walls. There is no need to go into to much detail what you want is a basic representation of the room, the most important thing is that it is tracked solidly with minimal drifting.
You can then apply materials to these objects to behave how they do to their environment in the real world. Your desk will receive a shadow, it will also receive ambient occlusion, it will also reflect(not like a mirror), light bounces around like mad and one of the big flaws in your purple box is it is hardlit (dark on one side)not even underside of your desk with no direct light is dark.
The best material in your arsenal to texture the room will be "matte/shadow/reflection". You'll then need to add light, use a couple of lights to emulate light sources(the ceiling light, the screens etc) then use dozens of very dim lights to emulate ambient/reflected light. Example; Place a good 5 or 6 lights on the table surface and make them a very dark brown but turned down to 10% strength. As these represent the light bouncing off the table exclude the table from the light/shadow properties.
Once you've applied the above rule to tracking a "scene" you can then insert anything and it will look as if it belongs their. If the object is reflective you might want to look at HDRI environment lighting/texturing. If you really want to get clever you can use caustics and IOR's and insert transparent objects. Also with a little tweaking render object settings you can have the artificial object pass behind real world objects convincingly without post production masking....but first thing first... practice your observation and read up to to what happens to light and how it behaves when it hits objects(it bounces).