CGTalk - shadow in composite

braw

12-09-2003, 10:04 PM

I'm fairly new to Lightwave and compositing in general. I am looking for suggested techniques for dropping a 3D object into a video taped scene with shadow. I have tried modeling a surface in Lightwave for casting shadow but when I check "unseen by camera" for the plane, the shadow doesn't render.

Any suggestions would be appreciated.:drool:

leigh

12-09-2003, 10:26 PM

Simply render out a shadow pass. Go to the Advanced tab in the Surface Editor and set the surface Alpha mode to Shadow Density. Render the sequence out as a 32-bit image sequence, take it into your comping package, and voila! You have a shadow pass :)

braw

12-14-2003, 07:12 AM

Thank you so much. I knew it could be done and I knew I was going about it the wrong way.

Appreciate the tip!:thumbsup:

Ikarus

12-14-2003, 06:44 PM

I've know about the "Shadow Density" option, but is there a way to do this for reflections as well?

Whylee

12-14-2003, 09:29 PM

If you go into the effects panel (ctrl F8), add an image filter called "Buffer Export" and go through it's options you'll see things like specular shading, shadow, luminous, etc. You can export many layers of information this way. Or add the "PSD Export" and you will see the same thing.

One thing to watch out is these features will write out a frame when you hit F9 or F10 so disable them until you're ready for final renders.

Kvaalen

12-14-2003, 09:41 PM

If you want to do it all in LightWave, you can just create a plane that matchs the ground and set the diffuse sharpness (under the advanced tab in the surface editor) to 100. Set the taped footage as the texture with projection type set to Front. Set the backdrop to be that same footage. And that is it.

I haven't done this for a long time so I might have left a step out, but I don't think so.

Hope this helps :thumbsup:

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