Hi all.

This has probably been done before, but if so I've not seen it:-)

I wanted to create a 1-way mirror for use in Vue.
Now, why would I want to do that? If I look from 1 side it's a mirror, from the other it's glass and I can't see both sides at once...

Except if there's another mirror behind the 1-way mirror...

In that case then anything between the two would get reflected ad-infinitum, whereas anything the other side of the 1-way wouldn't get reflected.

I couldn't find any way to do that directly in Vue, so I created a simple box prop and gave it material zones for Front, Back and Edges.
I imported this into Vue and textured it with a mirror surface on the Back and a simple glass on the Front. (The Edges don't matter, they're just opaque.)
The trick was to make the Back surface (the mirror) 1-sided. Now looking from the front, you can see through the back, but looking from the back you see reflections.
Then I put a plane behind the 1-way glass, tilted it vertical and mirrored it.

Boxed the whole thing off with planes, put some stuff between the two mirrors (red ball, some lights), added a (green) ball in front and...

Well, you can see the result. I haven't bothered to tidy it up properly..

Cheers,
Diolma