Decal problem with Path Tracer

[Peter Milner]

You can see from these images that something is not right with the Path Tracer.

The decal is applied to a region. The text is colour masked to allow the applied material to show. The surrounding area is transparent with IOR set to 1.0.

[Roy Hirshkowitz]

What's your guess, is this a newly introduced problem or one that's been there for a while?  In any case, I'll likely need a test model + decals.  Upload when you get a chance.

[Peter Milner]

I'll set up a test sample and send it to you tomorrow.

I thought it may disappear if I left it to run for longer, but it doesn't.

[Roy Hirshkowitz]

There are a couple of obvious things to check.  Coincident surfaces can screw this up, for example.  Units and distance from origin.

[Peter Milner]

Here's a stripped down model and the decal.

No coincident surfaces, units set to mm and near the origin

[Peter Milner]

Moving the region further from the wall, it seems as though Path tracer isn't recognising the double sided switch on the decal.

Turn double sided off under packet tracer and you get the same effect.