Low illumination issues

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edivers
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Joined: Thu Sep 29, 2022 4:19 pm

Low illumination issues

Post by edivers » Fri Nov 11, 2022 8:19 pm

Hi, I am designing an interior (attached) in dark finishes and have noticed that there is insufficient light cast from the window (used skyportal) plus 3 overhead lights (4" pin, 220W, 13 efficacy)and a lamp (lower power pin) to illuminate the room. I have set exposure to 15. Since I'm new at this, I'm noticing a few things I don't understand (besides the low lighting level)

-Although there is not much light, the ceiling is glowing with it! I realize the bulbs are closer to it, but wondering if there's a way to redirect the light downward.
- The light sources themselves (naked bulbs) read as black blobs. Do I need to upgrade to Pro to get fixtures to address this problem?
- There is no light spilling onto the floor and the side of the sofa from the window. I realize this may have to do with the portal, but I don't know how to make natural light come in!

Obviously, I'm new at this, so wise counsel is welcome. :-)
Attachments
4 inch lights.jpg
4 inch lights.jpg (244.67 KiB) Viewed 559 times
Ceiling.jpg
Ceiling.jpg (362.54 KiB) Viewed 559 times

Fletch
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Re: Low illumination issues

Post by Fletch » Fri Nov 11, 2022 10:37 pm

:welcome: edivers,
It is not clear why your lights look like that. If you can share a link to the scene I can diagnose the issue properly.

My guess is that the lights are not built correctly.

Please follow the video tutorials.
See also these free sample lights for you to try.
from the Freebies section of the forum.
Subject: Can Light and 2x2 or 2x4 Standard Ceilight Light Components

Pro users have access to more than 130 free very high quality light fixtures ready to go in Twilight Render.
Subject: Light Components package Image

It looks like your curtain material is blocking the sun from coming in. Try the "curtain Thin" material.
Subject: Translucent Material comparison

For explosure/tone mapping try Filmic and try changing the value for Shadow from .1 to .2, then .4, then .8, and so on. Do this for Midrange and Highlight values by doubling their values up and down from their default. I like whitepoint at 1.00.

See also about exposure:
ACES vs Filmic : When do I use Filmic versus ACES when Tonemapping?


Have you watched these videos? Did you build the portal exactly as shown in the video?


edivers
Posts: 7
Joined: Thu Sep 29, 2022 4:19 pm

Re: Low illumination issues

Post by edivers » Tue Nov 15, 2022 5:39 pm

Hi Fletch,

Thanks for the link to the lights. I've installed them and you can see from the photos that although they are in the model they do not illuminate. Also, I noticed that it takes 400W to get an illuminated thumbnail in the light editor.

I'm sure I'm missing something obvious -- but what? Once I have functioning lights I can explore the Filmic suggestions.

Thanks!
Attachments
Lights in model.PNG
Lights in model.PNG (678.71 KiB) Viewed 517 times
400W.PNG
400W.PNG (69.95 KiB) Viewed 517 times
recessed lights not working.jpg
recessed lights not working.jpg (228.37 KiB) Viewed 517 times

Fletch
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Re: Low illumination issues

Post by Fletch » Tue Nov 15, 2022 10:56 pm

Without a download link to your scene I can not guess what you are doing wrong. I apologize but I am not magical or psychic. Just a regular old human.

It's pretty obvious that when you inserted your can lights they did NOT cut holes in the ceiling as they should, which likely the ceiling is a group or component, and you need to open it for editing before you place the lights so that they can cut holes. They will not shine light without that.

This is covered in the video tutorial as well.

Have you watched and tried to replicate the work done in the video tutorials about lighting?


edivers
Posts: 7
Joined: Thu Sep 29, 2022 4:19 pm

Re: Low illumination issues

Post by edivers » Sat Nov 26, 2022 7:23 pm

Hi Fletch -- here is the download link https://www.dropbox.com/s/uksjz621v90ev ... 3.skp?dl=0

I watched the video and successfully placed a spotlight to illuminate the painting (yay!) and plopped a point light in the middle of the room with 2900 lumens.

I also pulled the pre-made recessed lights down from the ceiling and now you can see they are on, however, they aren't illuminating anything. I do need some light on the rug and the side chair.

Exposure is still set consideably higher than the suggested amount to get a reasonable level of illumination.

Thanks for anything you can do to shed more light (!) on what I'm missing here.
Ellen
TEST2 - center_spot_recessed.jpg
TEST2 - center_spot_recessed.jpg (176.94 KiB) Viewed 405 times

Fletch
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Re: Low illumination issues

Post by Fletch » Sun Nov 27, 2022 3:37 pm

:>: :>: :>: Download Twilight support edited scene here.

render with easy 09 + Fastforward denoise addon for Twilight. This render was done in 3 minutes.
temp3-techsupport01.jpg
temp3-techsupport01.jpg (582.62 KiB) Viewed 389 times
Your lights are strange. The lights are all grouped together. Then the ceiling is in a completely different group by itself. This means that the ceiling plane is cutting through the middle of the light fixtures. This problem is demonstrated along with the solution in the video tutorial linked above. They must be together in the same group, or in no group at all... but in the scene together without being grouped.
problem-1.jpg
problem-1.jpg (57.19 KiB) Viewed 397 times
Open the ceiling group and insert the lights from the components window again so that they can cut the opening.
Or
Cut holes in the ceiling and delete that circle part out that is blocking the light object from shining into the space. (this is the option I chose. I intersected the ceiling plane with the model and deleted the circles that were cut by sketchup.

Suggestion 2:
the radius of the light. This is discussed in the video tutorial. The radius of the light is best kept at 2 cm or 1" when starting out. The radius of your light objects is 5" which is a 10" or 25cm diameter light object so that now the light object is large than the light fixture itself. This results in errors. try .5" (1cm) radius they also render faster that way.
problem-2.jpg
problem-2.jpg (91.87 KiB) Viewed 397 times
Suggestion 3:
Your light power for the ceiling cans is 400w which is way too strong. 100w is plenty.

Suggestion 4:
Curtain material is a flat default material. Use Template>Translucent>Thin Curtain and for the darker curtain try "thick curtain".
problem-4.jpg
problem-4.jpg (83.08 KiB) Viewed 396 times
Suggestion 5: paint on wall try Template>Paint>Eggshell

Suggestion 6: other materials
1 glass table try Template>Arch Glass>Common and set color to pure white
2 set ceiling color to 70 or 75% white
3 paint wall behind curtain to be a light beige or 70% white.
4 Lampshade try Template>Translucent>Shade
5 wood floor try Template>Advanced Reflection > wood mapped set reflection to 50% grey and bump to SketchUp bump size set to 0.1

Suggestion 7 Sky Portal built incorrectly.
The face to be painted can only be the front face of the box you built to cover the window. The face must be flipped around (reversed) so that the side painted is facing into the space. See updated file.

Suggestion 8
avoid floating spots or pointlights in spaces. Only put lights where they would normally go in the scene.

Suggestion 9 bring back and side walls closer to the scene so that they can reflect more light sideways onto the objects. Or add a couple soft light emitting planes to fill the back and side lights.

Suggestion 10 Use Filmic Exposure set Filmic Whitepoint to 1

Suggestion 11 Set Camera Field of View in SketchUp to 55 instead of 35, it allows you to get closer to the subject and looks better, also allowing you to get the side wall on the right to move closer to the scene to bounce more light.

Suggestion 12 - point light in the floor lamp is conflicting with the 3D pole geometry and therefore not working correctly and throwing errors. move it, and lower the power a little... 75 watts or 100 watts. Set color to HSV 36 36 100 Add a spot as done in the example edited scene linked above.

Suggestion 13 - Add thickness to walls, floor, and ceiling. Avoid any z-fighting (where two surfaces share 3D space with one another)

Suggestion 14 - adjust Filmic exposure as in scene linked above and render with easy 09 - buy Twilight + Fastforward denoise addon for Twilight at 50% off for the next couple days only! Then use Fastforward denoise. This render was done in 3 minutes.

Suggestion 15 - purge the scene to make it a much smaller file use purgeall.rb

Fletch
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Re: Low illumination issues

Post by Fletch » Sun Nov 27, 2022 8:22 pm

here is Medium + and only half the resolution of the image above.
It took 1h20m to render on Easy 05 Med + render setting.
This is because of the sky portal and the light emitting surfaces I added to get the back of the chair and side of the couch lit up a bit. If you use Easy 1-7 render settings, replace the emitter planes with large soft spot lights and delete the sky portal Disable sun/sky and use a single light emitting plane/surface in place of the window glass or sky portal. That one emitter plane you then will have to tweak the power until you like the results. I often use this technique instead of a sky portal.

sky portal forces all light photons from sun and sky to come through the window. this is why it makes easy 1-7 render settings work much more slowly (greatly increased number of photons) but actually speeds up Easy 9 or easy 10 render settings. Those unbiased settings want the light sources to be close to the surfaces its rendering for quicker cleaner results.
Attachments
livingroom05.jpg
livingroom05.jpg (183.02 KiB) Viewed 380 times

Fletch
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Re: Low illumination issues

Post by Fletch » Mon Nov 28, 2022 9:37 am

using emitter plane in window instead of sky portal
disable sun and sky
wanted lights that are mimicking light from windows or doors in the adjacent rooms or spaces - placed spot lights shining onto white wall surfaces to make soft light to the right and behind the camera.
Attachments
techsupport.jpg
techsupport.jpg (128.27 KiB) Viewed 370 times

edivers
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Joined: Thu Sep 29, 2022 4:19 pm

Re: Low illumination issues

Post by edivers » Wed Nov 30, 2022 6:09 pm

Wow, Fletch, this represents a lot of work on your part -- thanks for fixing the daylight issue and making the suggestions about using bounced light to enhance the overall lighting. I confess that I'm a bit overwhelmed. Is it possible to hire someone (you? someone you know?) to just get the lights in and set the materials? If this were a software I would be using on a regular basis I would put in the time to learn it, but it's a steep learning curve for a one-time project.

THE PROJECT: I'm a design theorist/researcher and this image is for an architectural color psychology study where the same room will be rendered in six different color palettes (dark, light, neutral, vivid, etc.). The color design part of this project is challenge enough for me -- once the lighting is resolved I have to change all the finish colors (not to mention figure out how to take the same rug and change its color palette six times . . .)!

One thing I'm seeing right away that the lamp which is a wood base with a semi-translucent linen shade is rendering as a shiny white base with an opaque black shade. This is the kind of thing I want someone to just fix. Any thoughts on where I could get this help?

Thanks :-)
Ellen

Fletch
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Re: Low illumination issues

Post by Fletch » Wed Nov 30, 2022 8:57 pm

I gave you the file above, did you download?
:>: :>: :>: Download Twilight support edited scene here.

The lamp post problem was that the faces were reversed. I think this was fixed in my file I shared. I reversed the faces and painted the front face. But it's possible I did that after I had already posted the file above. Download again.

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