Shadow catcher weirdness

[gordonrobb]

Firstly, let me say I love the shadow catcher feature with Octane. Load an object, click on the floor and make it a matt object. Boom. Looks great., but what is the weird line of shading difference? It's diagonally across the floor object.

[FrankPooleFloating]

Hmm.. Do you have smoothing on for floor?.. Quads are automatically tripled in engine, right?.. and this line is prolly where the tripling would be...

[gordonrobb]

I set up the scene again to try it and when I first set the surface as Matte, the line wasn't there with Smooth on. So I thought, maybe it is only there with smooth off. Clicked it off, and hey presto the line appeared. Great, but when I clicked it back on, the line stayed there. So the tried both,pressing reload between and it's there regardless of smooth being on or not.

[gordonrobb]

Tried a box under the main object, and made it a Matte object with no smoothing. You can see the error is still there, and it is not in line with surfaces being tripled.

[juanjgon]

Can you export the scene to the Standalone to see if this problem is also there? ... you can use a more simple scene, only with cubes perhaps, and if you find this issue in standalone we could send the scene to the Octane developers to check it.

-Juanjo

[gordonrobb]

OK, I've traced what is causing the problem at least. I have a light inside the cab that when its on, that weird black line appears. And yes it happens with exported geometry too. It's not a shadow though. With other lights, you can see a shaddow, and the weird black lines too.

Light on

Light Off

Problem in Standalone

[FrankPooleFloating]

Did you by any chance mess with the default Ray Epsilon? (like less than 0.0001).. if you crank it down, things can start getting pretty funky... Or maybe up is correct word. I know that if you kill a zero or two - like 0.01 or 0.001, you can start seeing odd things.

I would also be very curious what would happen if you make your floor have something like more than 12x12 polys (couple hundred polys - whatever) and bend it ever so slightly across the whole floor. (use bend tool and curve it by 1 degree)... please try this and report back.

[juanjgon]

Yes true ... a problem with the scene scale (too big to too small) could render this kind of artifacts.

-Juanjo

[gordonrobb]

Will need to wait till tomorrow now. I can definitely say I have not messed with the ray epsilon in Standalone. Not sure about LW

[Tommes]

Actually, I think there is a bug when using the matte schwitch (shadow catcher) of diffuse material. Every time you have a light in the scene there are some shadow issues.

Sample image with the dark square on the right side. This is the shadow of the light. But the switch that it should cast shadows is off, of course.