View Full Version : Green screen, chromakey plugin Tutorial?

3d user
01-23-2008, 03:39 AM
I am trying to achieve a Green screen, chromakey solution using LW (7.5) surface editor.

What I have is a person with lit green screen behind. I've created a TV-news set with lightwave (3d desk, etc). For the newsanchor I have flat box object with front projection. I am having trying to set layers do that only the person is visible. Just like they do in TV.

If possible I don't want to do multiple passes. I did a test run in Sony Vegas 7 and I could remove the greenscreen nicely. I want to do the same in LW if possible. The source material is DV.

3d user
01-23-2008, 05:13 AM
I've used am alpha layer and the original green screen. Alpha has taken out the green screen but I am left with the original color of the box object. How do I make that invisible. Using Tranparency 100% will make the whole object invisible.

01-23-2008, 06:14 AM
Use the alpha layer as a clip map for the object (or a transparancy map).
That should remove the white parts of the image above.

3d user
01-24-2008, 02:20 AM
I got it to work but with green edges. It appears that LW masks out pixels that are totally black. When I tested the same in Sony Vegas I got got the green edges nicely away.

Is there a plugin in LW that does chromakey operations better?

01-24-2008, 07:39 AM
Not as far as I'm aware. Dpont did do some lovely nodal post processing tools and I asked him if he had any plans to do a keyer, but he doesn't. I was going to have a stab at it myself, but seemed it bit pointless when you have a compositor.
If you're using a clip map, the pixels that are <50% grey should dissapear.
I'm not sure why it would work in Vegas and not in LW.
It's a hack, but you could try making your matte texture 0.1% larger...it may sort out the edges and retain a good matte around your subject. Bit of a rubbish solution though, sorry.