Author Topic: shadowcatcher not working right  (Read 589 times)

2019-12-10, 11:40:11

Tok_Tok

  • Active Users
  • **
  • Posts: 97
    • View Profile
Hello,

I have an issue with the shadow catcher material. In the screenshot below you see my scene, in there I have a flat box with a lot of lights shining on it (there are suppose to be other things on the box but I can't show that), some of the objects are Included in some lights and others are excluded in other lights. In ALL lights have the bottom plane is excluded except for the light blue plane you see. This light is creating the blue glow, which I expect to see in my alpha channel. But now I get all kinds of shadows and artefacts in the alpha channel. There is also a rectangle showing up in the alpha channel somehow.

Below the first image you can see the alpha channel when I hide all the lights except for the blue plane, this is how I expected it to look because the blue light is the only light that should be affecting the shadow catcher plane.





Is this correct behavior? The obvious fix is to render 2 images but I prefer not having to do that. Btw I'm on corona 4 so upgrading might help but I prefer not to do that just yet.

Thanks!

2019-12-10, 13:33:54
Reply #1

GeorgeK

  • Corona Team
  • Active Users
  • ****
  • Posts: 155
  • George
    • View Profile
That's a TR isn't it  ^^? Can you please provide the scene with no-materials or any extra assets you don't want to share, just the setup.
“Every artist was first an amateur”

2019-12-10, 14:25:26
Reply #2

Tok_Tok

  • Active Users
  • **
  • Posts: 97
    • View Profile
Thanks, I sent you a PM.

2019-12-10, 16:38:59
Reply #3

Tok_Tok

  • Active Users
  • **
  • Posts: 97
    • View Profile
Another thing that I noticed that is weird, is that Corona Lights and Corona Light materials don't show up as a reflection in the alpha of a shadow catcher material. But a normal Corona material with an emitting component to it, does. So now I'm replacing lights that should be reflective on the ground plane by a material that's emitting light. But the problem is that a material doesn't have all the options a normal Corona light does.

2019-12-11, 08:42:28
Reply #4

GeorgeK

  • Corona Team
  • Active Users
  • ****
  • Posts: 155
  • George
    • View Profile
Another thing that I noticed that is weird, is that Corona Lights and Corona Light materials don't show up as a reflection in the alpha of a shadow catcher material. But a normal Corona material with an emitting component to it, does. So now I'm replacing lights that should be reflective on the ground plane by a material that's emitting light. But the problem is that a material doesn't have all the options a normal Corona light does.

Investigating both issues, and will get back to you as soon as possible. (note, coronalight582-579  didn't exclude the plane001 but fixed this not that it matters much to what you've reported just a thing to fix.)
« Last Edit: 2019-12-11, 08:48:01 by Corona_GK »
“Every artist was first an amateur”

2019-12-11, 12:17:35
Reply #5

Tok_Tok

  • Active Users
  • **
  • Posts: 97
    • View Profile
Thanks. Yes I noticed and that seems to fix it for that scene.

I think i fixed it, I remember talking in another topic about this and a user told me that when the background color is a full black some stuff doesn't work with the shadow catcher material. Changing the bg colour to the darkest tint of black makes it work for some reason. The weird thing is that I have scenes where this works and scenes where it doesn't.

I also have a scene with only one light, excluded the floor plane but it's still showing up as a reflection, only when I turn off "Occulde other lights" it disappears. It weird showing up at all because in my previous tests a Corona light wouldn't show up in the reflection at all. But that might be because the background colour is set to a value 21. Changing the background color to 21 makes the alpha channel almost completely white.

Hope this helps

2019-12-11, 12:44:57
Reply #6

Tok_Tok

  • Active Users
  • **
  • Posts: 97
    • View Profile
Another case that's also weird:

There are no lights in the scene just the box and a plane with a shadow catcher material. The box is reflecting in on the plane. This shouldn't be right, because there is no light hitting the box.

Sorry if I'm sending too much information, I'm just reporting what I bump into :)

2019-12-11, 14:10:11
Reply #7

GeorgeK

  • Corona Team
  • Active Users
  • ****
  • Posts: 155
  • George
    • View Profile

There are no lights in the scene just the box and a plane with a shadow catcher material. The box is reflecting in on the plane. This shouldn't be right, because there is no light hitting the box.

Sorry if I'm sending too much information, I'm just reporting what I bump into :)

Not at all thanks for the input and glad to help.

I reproduced all of the above that you've mentioned and made a report on it. On this case what you are seeing in alpha is actually the shadow of your object on the shadow catcher plane, I am not in a position to explain why and how but yes it looks strange. You should know that it's not related with your corona version, it's just a shadow-catcher issue.

Reported.
(internal id=433434133)
“Every artist was first an amateur”

2019-12-11, 14:51:07
Reply #8

Tok_Tok

  • Active Users
  • **
  • Posts: 97
    • View Profile
Thanks for your help! Hopefully this can be fixed soon! It's kind of frustrating that this is still a bug in the software. I need to make deadlines and this testing takes a lot of time. As I said I started a topic on this about a year ago and the same issue surfaced. I was hoping it would have been fixed by now!

In any case, thanks for your help!

2019-12-11, 22:25:02
Reply #9

sprayer

  • Active Users
  • **
  • Posts: 698
    • View Profile
it's fine imho, you set black enviroment and no light and reflected shadowchater, it catch black reflection of object