Environment map for reflections only?

Support Basics & Interface
1

I have searched and searched but cannot find the answer to this question.

Is it possible to use an HDRI as a spherical environment map and turn off the primary visibility? I want it to show up in reflections but not in the background so that my reflective chrome object can have an alpha channel.

Thanks in advance.

2

I guess I’ll just render out an alpha channel in a separate pass. I still would be interested in finding out if this is possible though if anyone has any ideas.

3

This is a good question. I would like to know more about the HDRI too.

I have seen a lot of good looking projects that use it, but most of them are closeup views of small objects. I have used HRI myself, for little projects.

Is there a way to use HDRI in a large scene, without the HDRI image being seen in the background? What is the correct type of HDRI image?

4

You could probably give your Object an EnvMap Texture and render with the HDRI. Save the EnvMap and rerender without the HDRI and set the Render to Premul or Key in F10 with RGBA and a Format that supports Alpha.

%<

5

Yep, that’s what I ended up doing. I just turned off all of the lights and shaders and rendered out a simple alpha pass then threw them back together in After Effects. Still, it might be nice to have the option to toggle on and off primary visibility, visible in reflections, visible in refractions, etc.