Reflections on a matte object..

Hi there, I am compositing a 3d model over some quicktime footage. I have created a plane underneath my object with a material that has ‘onlyshad’ selected so I can cast shadows from my object on to the plane, without the plane itself being seen.

I would like to do the same with reflections. Is there away the plane can be transparent but show reflections?

3dsmax has a option for this, is there one in Blender?

Or do I have to use nodes to achieve it?

Much appreciated,


I wish there was a button like OnlyShad for reflection. It s on my wish list. OnlyReflect. But it does not exist. this means you can not get reflections with an alpha out of blender. At least i have not been able to figure it out.

You can kind of fake it with two planes, but you won’t get an alpha. Each plane handles one aspect. One for shadow and the other plane for reflection.

I am attaching my 2-planes solution. Append the floor scene, then use CTRL-L to link in both planes to your current scene. Give it a try, may be it will help.


ras_floor_reflection_1c.blend (171 KB)

Thank you so much. I really appreciate it. I may try and add the suggestion of ‘Onlyreflect’ to Blenderstorm. :slight_smile:

Only Reflect == 100% reflection, HAHAHA!

You’ll need to add a full copy of the scene (faces sharing the same space within the same scene == bad juju). In the second scene make the shadow only plane 100% reflective and disable it’s Only shadow option. Add this into the compositor of the first scene. Now set this reflective only plane’s alpha channel via the alpha channel of the shadow only plane (which should reside on it’s own, lonesome render layer). Scenes are chosen in the compositor via the little set of arrows on the bottom left of any render layer node.