Messages

1

[Max] I need help! / Re: Problem with Alpha that has "holes"

« on: 2018-11-26, 13:35:38 »

Actually - my initial setup was with scattered grass blades - and I got exactly the same result. The problem is with the material shader and not the geometry. I switched to noise because it was simpler to do for a large area when all that was important is the jaggered edges of the shadows.

Also - I cannot do it in a fake setup because it's not a still I'm after - but an animation - so the ball bounces and rolls.
I was actually really looking forwards to rendering this using Corona but may go back to VRay since I don't think I can rely on this odd behavior of the matte/shadow.
Maybe it's the correct way the shadow-catcher works, but the matte solution for Vray does it correctly - the way I need it. I think the proper fix for the shadow catcher is - instead of focusing only on the areas that get the shadow - it should otherwise focus on the areas that don't get light. Sounds like it's the same thing but it's not.

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[Max] I need help! / Re: Problem with Alpha that has "holes"

« on: 2018-11-26, 10:48:40 »

If this is the correct way ShadowCatcher works then it's a problem. It doesn't imitate real world. If I place a ball on the grass, the grass-blades faces that don't point towards the light source - in real world - will still be in the shadow. Using the Shadow-Catcher they'll be lit. This would be wrong.
What, then, would be Corona's method of solving this wrong behavior? A different material other than Shadow-Catcher?

Thanks.

3

[Max] I need help! / Re: Problem with Alpha that has "holes"

« on: 2018-11-26, 10:07:41 »

Some comparisons:
Simple teapot on a surface with a large noise level (to see the problem more clearly)
When rendered with Vray using the MtlWrapper, Matte Surface (alpha contribution -1), including shadows and affect alpha - I get a proper opaque alpha with jaggered edges like I want.
When rendered with Corona using the Shadow Catcher - I get "holes" in the alpha channel.

In short - the Shadow Catcher isn't working well.
Using Corona 2.0, Vray 3.60

4

[Max] I need help! / Re: Problem with Alpha that has "holes"

« on: 2018-11-26, 09:26:37 »

Did a small similar test with Vray (teapot instead of sphere) - and that alpha worked fine. Opaque the way it should be.
Any ideas on what's wrong with the Shadow Catcher (Corona 1.7.4)?

5

[Max] I need help! / Problem with Alpha that has "holes"

« on: 2018-11-25, 10:32:19 »

Hi,

I have a very simple scene - a ball on a surface with a single light. The surface has noise on it so that the shadow on it will be rough and will look like shadow on grass. I am using the Corona Shadow Catcher on it.
The final image of the ball and the shadow will be composited on a photo of grass.
The problem is - the alpha channel has holes in it where the shadow is. So the lit grass from the photo show through the holes of the alpha - where they should actually be included in the shadow of the ball.
It looks as if the shadow catcher only catches shadows on faces facing the light source but not in the volume of the whole shadow.
Does anyone know of this problem and how to correct it?

Thanks!