Weird shadows when using emitters

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Tetiana
Posts: 5
Joined: Fri Apr 09, 2021 5:59 pm

Weird shadows when using emitters

Post by Tetiana » Wed Jun 30, 2021 8:54 pm

Hi All,

I'm trying to get a picture somewhat similiar to https://www.archdaily.com/905081/xiangc ... project=no. Currently I'm quite far from it :D and I stuck with some emitter materials.

This is how my model looks like in Sketchup (please ignore light cones, they just some remaining artefacts of my experiments and they are disabled for rendering)
2.png
2.png (1.11 MiB) Viewed 5656 times
As a source of light I use tubes covered with emitting texture
3.png
3.png (229.65 KiB) Viewed 5656 times
And this is what I get after a few rounds with Interior+ and Denoiser (image is kinda blury, it looks touch better if not stored in jpeg :) )
1.jpg
1.jpg (204.02 KiB) Viewed 5656 times
What I do not understand though, is why I have this weird shadow zone just before the building, I'm pretty sure this is not how light should work. Is there any way to fix this? Or I'm using entirely wrong technique here?

Fletch
Posts: 12896
Joined: Fri Mar 20, 2009 2:41 pm
OS: PC 64bit
SketchUp: 2016-2023
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Re: Weird shadows when using emitters

Post by Fletch » Thu Jul 01, 2021 6:02 pm

the "shadow" is not a shadow, but rather, it's the spot lights you are saying we should ignore. Those spot lights do not exist on the original building you are trying to recreate. Or--- they are specular highlights on the pavement and they are accurate reflections.

Try to directly copy how the lights would be built on the real world building, and it works much better.
Have a look at this test scene. I think the spot lights look better than the emitter. *emitter is bottom row of lights and spots are in the top 2 rows.
Attachments
test-TWL.skp
(676.36 KiB) Downloaded 303 times
Untitled-3.jpg
Untitled-3.jpg (293.7 KiB) Viewed 5643 times

Fletch
Posts: 12896
Joined: Fri Mar 20, 2009 2:41 pm
OS: PC 64bit
SketchUp: 2016-2023
Contact:

Re: Weird shadows when using emitters

Post by Fletch » Thu Jul 01, 2021 6:59 pm

Here with lighter pavers with some specular. Notice in original photo of building IRL that the pavers are not reflective.
Added the cut-outs to the fins so that the glass of the curtainwall is seen beyond, more like the original design.

SketchUP scene attached for your convenience. :hat:

Tone mapping choices are critical! Note the tone mapping settings in the attached SKP file. See also tutorial below.

Subject: ACES vs Filmic : When do I use Filmic versus ACES when Tonemapping?
Attachments
test-TWL_Scene 3.jpg
test-TWL_Scene 3.jpg (796.49 KiB) Viewed 5633 times
test-TWL.skp
(719.44 KiB) Downloaded 300 times

Fletch
Posts: 12896
Joined: Fri Mar 20, 2009 2:41 pm
OS: PC 64bit
SketchUp: 2016-2023
Contact:

Re: Weird shadows when using emitters

Post by Fletch » Thu Jul 01, 2021 7:34 pm

On closer inspection of the original design it looks like it's a pole, and the lights are shining on a curtain/sail/screen that is likely a perforated screen material. This fabric/screen material is only attached where the lighting is desired. I could be wrong, the details are not shown clearly in the photos.
Attachments
Untitled-2.jpg
Untitled-2.jpg (413.32 KiB) Viewed 5628 times

Tetiana
Posts: 5
Joined: Fri Apr 09, 2021 5:59 pm

Re: Weird shadows when using emitters

Post by Tetiana » Sun Jul 04, 2021 3:46 pm

Thank you very much for recommendations and files attached! This is exactly what I tried to achieve :hat:

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