I'm trying to get something to be invisible, but I want objects to be reflected in it. I can do this using opacity on the material pallet, however, this causes the objects reflection to have an alpha value of 0. I would like the reflection to at least have an alpha value of 0.5, is this possible?

In the Geometry Object's parameters, turn on Render > Phantom.

I've already done that, and it's not what I want. If it's phantom, it won't show any reflections. I want an object to be reflected in it. I don't want it to reflect in anything.

Here's an example of what I want.

There's a grid below the Möbius Strip, and it's has an opacity of 0. But this causes the reflection to also have an opacity of 0. I want the reflection to be translucent, with an opacity of something around 0.5.

So you could see the reflection, I had to remove the alpha channel when saving the image. But what it normally has is everything but the strip itself with an opacity of 0.

Use the Reflective material from the gallery and turn the base/background colour to black. You might also want to turn off Use Index of Refraction.

This is very crude but will give you an idea how to build a shader that will do this in VOPS — wire the color output from the reflective vop into the output's Cf ( color) and , via a luminance and float-to-vector conversion, into the Of ( alpha). see attached pic.

It sounds like you just want it adjust it's behaviour in the light linker? You can tell objects not to appear in reflections there.

Boomtown has exactly what I want. Thank you. Except I have no idea how to work with VOPs. Guess I'll go look for tutorials and look through the help manual.

UPDATE: Okay, I learned how to do what Boomtown suggested just by messing around and pressing buttons. Thanks a ton, it worked perfectly.

Hey, anyone know how to do this, but instead of with reflection with a shadow?

you have Shadow Matte VOP for this

Alright, I'll go check it out.

UPDATE: Yep, that's what I wanted. Thanks.