The new Pixel Depth Offset value that materials can take is really nifty, but unfortunately it can only tell objects to render further BACK than they normally would.
I’d like a way to feed negative values into this parameter so that it can tell objects to render further FORWARD than they normally would.
In particular, this is useful for particle systems which use planar particles to represent volumetric objects. A particle will always render facing the camera but if it’s attached to, say, a hand socket, it will render THROUGH the hand. A negative Pixel Depth Offset value would allow me to force it to always render X units FORWARD, which would give it the appearance of always being in front of the position it actually exists. So a particle which is 25 units across could use a material with a -25 (or whatever the corresponding value is) pixel depth offset; this would make it appear to be a 25-unit sphere, since it would appear in front of objects within 25 units of it and always facing the camera.