About shadows and emission

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wasd
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About shadows and emission

Post by wasd » Fri Nov 23, 2018 12:31 pm

I have two questions.
1) Is it possible to disable shadow casting for certain mesh?
2) Is it possible to have material that looks like it emits light, but without actually emitting light?

I am trying to render incandescent light bulb. I have two options: make filament emitting light or use point light. With filament emitting light, the bulb looks pretty funny, so I choose to resort to point light for now. And for that one I need filament to not to cast shadows and be like emissive, but not emissive.
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B.Y.O.B.
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Re: About shadows and emission

Post by B.Y.O.B. » Fri Nov 23, 2018 12:49 pm

You could set the light bulb's glass shader to "architectural", this will let direct light through.
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Sharlybg
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Re: About shadows and emission

Post by Sharlybg » Fri Nov 23, 2018 12:50 pm

AND also try this setup :

viewtopic.php?f=4&t=483&start=50#p6827
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wasd
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Re: About shadows and emission

Post by wasd » Fri Nov 23, 2018 1:16 pm

B.Y.O.B. wrote:
Fri Nov 23, 2018 12:49 pm
You could set the light bulb's glass shader to "architectural", this will let direct light through.
So, the answer for both questions is "no"?
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B.Y.O.B.
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Re: About shadows and emission

Post by B.Y.O.B. » Fri Nov 23, 2018 2:09 pm

wasd wrote:
Fri Nov 23, 2018 1:16 pm
So, the answer for both questions is "no"?
Correct.

However, maybe you can do some tricks with render layers.
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lacilaci
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Re: About shadows and emission

Post by lacilaci » Fri Nov 23, 2018 2:44 pm

Not doable currently and every workaround is just painfuly slow and impractical.

However, I added this and other Ray visibility options per object as feature request on github. So hopefuly someday it willl be implemented as for archviz purposes it is super important.

wasd
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Re: About shadows and emission

Post by wasd » Fri Nov 23, 2018 3:07 pm

With rough glass the bulb looks just about right. I've also added some bump, like on the real thing, but it seems there's a bit too much of it.
Now render is 6 times slower.
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wasd
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Re: About shadows and emission

Post by wasd » Fri Nov 23, 2018 3:34 pm

Reference:
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Sharlybg
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Re: About shadows and emission

Post by Sharlybg » Fri Nov 23, 2018 3:39 pm

wasd wrote:
Fri Nov 23, 2018 3:34 pm
Reference:
if this is your reference you need architectural glass as BYOB told you. the scattering effect you see in your ref is due to camera Glare and bloom.
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wasd
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Re: About shadows and emission

Post by wasd » Fri Nov 23, 2018 3:53 pm

Sharlybg wrote:
Fri Nov 23, 2018 3:39 pm
wasd wrote:
Fri Nov 23, 2018 3:34 pm
Reference:
if this is your reference you need architectural glass as BYOB told you. the scattering effect you see in your ref is due to camera Glare and bloom.
Disagree. Take a look at the bulb. It is brighter than the walls. If I'd use arc. glass, the wall would be brighter (I checked that).
Besides, in my opinion, nobody needs architectural glass. In my personal list of the worst and useless things in Luxcore architectural glass is number one.

p.s. I know about bloom and glare, but it's beyond my research for now.
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