Curtain shader

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lacilaci
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Curtain shader

Post by lacilaci » Mon May 27, 2019 12:18 pm

How should I approach making curtain shader in luxcore, seems both matte translucent and glossy translucent don't let sunlight through at all.. why?

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B.Y.O.B.
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Re: Curtain shader

Post by B.Y.O.B. » Mon May 27, 2019 12:55 pm

As far as I know the translucent materials scatter the transmitted light in all directions.
If you want to have some light passing through in it's original direction, I would suggest to lower the opacity of the material a bit.

Could you post some reference images what kind of curtain you look for? Thicker cloth or lighter?

Here's a basic attempt by me, maybe it helps:
Attachments
only indoor lighting
only indoor lighting
sun passing through
sun passing through
3.PNG
curtain.blend
(100.48 KiB) Downloaded 31 times
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lacilaci
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Re: Curtain shader

Post by lacilaci » Mon May 27, 2019 1:02 pm

Thanks, well I guess it's either lowering or mapping opacity...
Which makes sense I guess but I thought that making the material transmit all light will also lower scattering/roughness.

I think I'm just too used to hiding curtain shadows completely

wasd
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Re: Curtain shader

Post by wasd » Mon May 27, 2019 5:38 pm

Curtain is a complex matter. First, for some reason SSS in luxcore is allowing less light through than expected. At least, less than I excpect, so it doesn't really looks realistic, unless you add some opacity.
Second is, if you look closely to fabric, it has a lot of holes between threads. That's the main reason the light comes through. The threads itself allow very little light through.
I use fabric black and white texture for opacity.
CPU Bidir (sometimes GPU Path) + Metropolis | Log Power | Core i5-4570

wasd
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Re: Curtain shader

Post by wasd » Wed May 29, 2019 7:07 am

wasd wrote:
Mon May 27, 2019 5:38 pm
I use fabric black and white texture for opacity.
Like this
Attachments
be.png
CPU Bidir (sometimes GPU Path) + Metropolis | Log Power | Core i5-4570

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