Ok, I’m doing some commercial work with blender now, and I need to make a chrome material. It reflects the world’s texture right now, but I need the background to render as alpha. How do I render just the reflection and not render the world?
This image is rendered in Blender Internal. Png Transparent background. Open this imgage in Gimp. If this works for you, I will give the settings.
use render layers. put object in layer one, and world / environment in layer two. activate both layers. in renderlayers, activate only layer one. that sould work, i think.
He is asking something different ^^
I assume he has a nice background which is mirroring in the actual object and wants to render the scene, showing the reflections of the environment but not rendering the environment. I ran into this too and have no solution so far 
In my special case it would be a Universe background with stars and nebulas and stuff. i want them to mirror in the spaceship but dont want to render the background. My only idea was to bake the texture and then use the texture without the environment… works for stills but not for animated stuff… ^^
So far I made planes with a texture and lights reflecting off the planes, this works. But I don’t want the planes to show up. I may tweak with render layers and compositing then I’ll get back to ya and give you a solution too.
Use a format which includes an alpha channnel like tga or png.
Choose RGBA from the FormatPanel and Key from the RenderPanel.
If your texture is mapped to the world, it will render alpha now.
Pat
Edit: Oh, I see, you ment something different. In this thread is a samplefile, which shows this done with renderlayers.
http://blenderartists.org/forum/showthread.php?t=135032
Actually I like my method better. I’m making a logo for cardweb.com, it’s an international site (in 3 different countries) so you will see my logo there in a few days =D
My new method is more of a cartoony chrome which is done using light gray and the default wood texture mapped to dark grey and them mapped the lights so when they mode the reflections move.
Thank you guys for all your comments, but I think I helped myself.
This reminds me how great of a community this is. I got 3 comments within 5 minutes of each other.
This is a very helpful community.