Author Topic: shadow catcher  (Read 1097 times)

2021-07-14, 20:09:54

iancamarillo

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I'm trying to add a shadow catcher floor but only have 1 light cast a shadow. But if I exclude other lights from the floor, the main light shadow in the alpha doesn't look correct. Not sure if this is the correct way to go about setting this up - any suggestions would be much appreciated! Thanks

2021-07-15, 09:21:28
Reply #1

Byteman3D

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This doesn't seem wrong actually, if I get it right.

The lights are area lights and lights of this size normally cast this type of shadows.
You can try the light's Directionality parameter to make the light rays parallel.

See if it helps.

Or simply reduce the light rectangle's size and/or move the light away from the object.

2021-07-15, 12:55:34
Reply #2

Avi

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On white, using your key light, this is the shadow you are generating so the alpha is correct that is being generated.

https://bit.ly/3z1WKJu


2021-07-15, 14:07:17
Reply #3

Frood

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But that edge in alpha at the left side when using compositing mode looks wrong. Like the light as an infinite plane is cutting into the floor and casts a (gi) shadow -  which would be a bug.


Good Luck


Never underestimate the power of a well placed level one spell.

2021-07-15, 14:50:40
Reply #4

Avi

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To fix the edge in alpha, simply make your plane bigger & it would fix. I don't think it's a bug. The bug however would be to get the alpha of the empty space in the 3ds max scene.

2021-07-15, 15:05:56
Reply #5

Frood

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simply make your plane bigger

I'm not referring to the edge where the plane meets the background but that edge (and area) marked with a question mark from here:





Good Luck



Never underestimate the power of a well placed level one spell.

2021-07-15, 15:20:22
Reply #6

maru

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I think that's a shadow of the left light object.
Disabling "occlude other lights" in this light's settings should resolve it.

2021-07-15, 15:47:07
Reply #7

Frood

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Disabling "occlude other lights" in this light's settings should resolve it.

Yes, but it's already turned off in the scene, just had a look at it.


Good Luck




Never underestimate the power of a well placed level one spell.

2021-07-15, 17:30:38
Reply #8

Avi

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Weird, but I am not getting the same when rendering from the same file.

I am using Corona 6 hf 2. Can you confirm for me what version of Corona you are using?

see my screenshot: https://prnt.sc/1bg9vsf

2021-07-15, 17:57:46
Reply #9

Frood

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Me either when rendering that scene with v6.1 - at least visible.

But if you use RMB in that VFB area, you see values !=0. I think the screenshot isn't from Corona VFB but from Photoshop where gamma is (wrongly) applied also to the alpha channel when opening a linear file. But anyway: the alpha is wrong: it should be plain zero there.


Good Luck



Never underestimate the power of a well placed level one spell.

2021-07-16, 04:35:38
Reply #10

iancamarillo

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Thanks for taking a look guys. I'm running 6 HF2. I get the casting but occlude is unticked like frood said.  The alpha in VFB is just saved to jpg but not sure why the saved jpg looks different from the VFB.

For now I'm rendering another frame with the only light I want shadows for. Is there any other way to set up a scene with multiple lights but only 1 shadow in the same render? lightMix?

Thanks again!

2021-07-23, 18:21:25
Reply #11

Frood

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but not sure why the saved jpg looks different from the VFB.

Presumably because gamma is applied.

@Avi: Have you confirmed and logged this one?


Good Luck

Never underestimate the power of a well placed level one spell.

2021-07-26, 15:42:38
Reply #12

Avi

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Hi,

Thank you for your patience.

I was able to reproduce the same using the latest Corona 7. I have logged this in our system and hopefully, it will be fixed in later versions of Corona.

Regards,
Avi

(Report ID=CRMAX-844)


2021-07-26, 19:40:45
Reply #13

Frood

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(Report ID=CRMAX-844)

Perfect, thank you Avi


Good Luck




Never underestimate the power of a well placed level one spell.