I bet it’s something very simple. I have a render layer that has two objects. One is shadeless white and the other is shadeless green. I need to remove the shadeless white part of the render so it is fully transparent (alpha 0). How do I do that? With the compositor naturally.
Naturally, by feeding the appropriate input to a set alpha node.
i don’t really understand ur question but i think u have to set down the alpha value.
even if you put glare effect on the mesh/object, it will still transparent.
I’ll simplify the example.
This is the image I get when I render.
http://img718.imageshack.us/img718/9589/ballwz.png
This the image I want to achieve using the compositor. Notice how the black parts have been removed and are transparent.http://img135.imageshack.us/img135/7937/balltransparent.png
You are saying that you have two objects in your scene and you want one of them to no be there.
The simplest way is to not even render the white object. Just remove it from your scene. Right?
Datanalle, why not just make it easy for people to help you by attaching your blend file to your post
No. I have four objects two in one layer and the other two in the second layer. Two of the objects are there to block out whatever is behind them (the black ones) and two of the objects I want to combine in the compositor (the colored ones) so they appear as one solid object.
I looked at the sample file you posted and couldn’t make much sense of it.
Anywayz, the idea behind the chroma key is terribly simple: you key the green/bluescreen footage and substitute whatever you want as a background using an alpha over node. There are dozens of videos on youtube demonstrating this process, both using blender and other softwares.
Yeah, chroma key is a bad way to go if you already have full control of the objects in the render. Keying is for footage solutions and typically produces jaggies along the edges.
I found an alternative method of doing what I needed with indirect lighting. On a second though my original method would not have worked anyways.