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GLBDAZ: IES for Emissive lights to lower rendering times
80
If you take a typical IES file, it doesn't quite work for emissive light profile when used as a ceiling light, that's because normal IES often assumes the light is upright.
e.g.
5346. 5331. 5272. 5162. 5007. 4849. 4662. 4456. 4248. 4036.
3771. 3466. 3041. 2443. 1714. 1177. 793. 493. 285. 168.
96. 71. 83. 85. 58. 20. 0.
Now, for it to work properly, it has to be inverted like this:
0.0 20.0 58.0 85.0 83.0 71.0 96.0 168.0 285.0 493.0 793.0 1177.0
1714.0 2443.0 3041.0 3466.0 3771.0 4036.0 4248.0 4456.0 4662.0 4849.0
5007.0 5162.0 5272.0 5331.0 5346.0
That way the light goes downwards.
It's not a problem for DZ lights since you can rotate them, but you can't quite rotate a ceiling, can you
?
Using AI like Claude of ChatGPT, you can upload any IES and ask it to invert it.
That way, your emissive ceiling lights will have a proper illumination and will make your renders way faster.
e.g.
5346. 5331. 5272. 5162. 5007. 4849. 4662. 4456. 4248. 4036.
3771. 3466. 3041. 2443. 1714. 1177. 793. 493. 285. 168.
96. 71. 83. 85. 58. 20. 0.
Now, for it to work properly, it has to be inverted like this:
0.0 20.0 58.0 85.0 83.0 71.0 96.0 168.0 285.0 493.0 793.0 1177.0
1714.0 2443.0 3041.0 3466.0 3771.0 4036.0 4248.0 4456.0 4662.0 4849.0
5007.0 5162.0 5272.0 5331.0 5346.0
That way the light goes downwards.
It's not a problem for DZ lights since you can rotate them, but you can't quite rotate a ceiling, can you
?Using AI like Claude of ChatGPT, you can upload any IES and ask it to invert it.
That way, your emissive ceiling lights will have a proper illumination and will make your renders way faster.
! REPORT
I'll give this a try. Have to admit, I've been cheating and using ghost lights (for everything) for quite some time!
REPLY
! REPORT
I have to admit: I have the most trouble with lighting in indoor scenes. That's why I've been rendering only outdoor scenes for years... even the ones that look like they're indoors 
Nevertheless - thank you very much for your efforts to bring some en- Light-enment to the DAZ stuff
Nevertheless - thank you very much for your efforts to bring some en- Light-enment to the DAZ stuff
REPLY
! REPORT
Pawngame
Karma: 34,254
Sun, Apr 12Well linear and point lights emit light in all directions, in that case, putting it at the center of the scene will do its proper work using flipped IES (regular IES work too but requires more lumen) and will send light on all directions.
Now, if you change Light Geometry to Rectangle or Disc, move it up to the ceiling and Rotate it -90 on the X axis, it will illuminate the floor.
If you rotate it 90 on the Y rotate (don't move to the ceiling) it will send lights from the side.
The only problem is that anything but point will show the light in your renders so set Render Emitter to Off to hide it.
Spot lights do work well if close to the ceiling (with a rotation to point downward of course), the only issue with spotlights is that IES do no work with them.
Now, if you change Light Geometry to Rectangle or Disc, move it up to the ceiling and Rotate it -90 on the X axis, it will illuminate the floor.
If you rotate it 90 on the Y rotate (don't move to the ceiling) it will send lights from the side.
The only problem is that anything but point will show the light in your renders so set Render Emitter to Off to hide it.
Spot lights do work well if close to the ceiling (with a rotation to point downward of course), the only issue with spotlights is that IES do no work with them.
Here's the difference between normal IES and Flipped IES, as you can notice, the top molding are way darker with regular IES.
Normal IES:
Flipped IES:
And since we're talking about lights, here's the explanation for indoor scenes using linear point lights.
Linear at the center of the scene, point geometry:
Light Geometry (Rectangle) at the ceiling and no rotation:
Light Geometry (Rectangle) at the ceiling with -90 rotation on the X axis:
Rotating Rectangle to 90 Y with IES:
Normal IES:
Flipped IES:
And since we're talking about lights, here's the explanation for indoor scenes using linear point lights.
Linear at the center of the scene, point geometry:
Light Geometry (Rectangle) at the ceiling and no rotation:
Light Geometry (Rectangle) at the ceiling with -90 rotation on the X axis:
Rotating Rectangle to 90 Y with IES:
REPLY
! REPORT
This is great info, thanks for presenting this. I also use ghost lights because I find that Daz lighting (and 3D in general) don't work anything like real lights. As a classically trained photographer I found this to be a huge disappointment. I only do interiors and have a pile of scenes with proper lighting that I've nursed to my liking. I may have to give your technique a go.
Thanks!
Rob.
Thanks!
Rob.
REPLY
! REPORT
Pawngame
Karma: 34,254
Sun, Apr 12Oh, IES actually are based on real lights, here's an example :
[LUMCAT] KH40A-Type III
[LUMINAIRE] KH40 with Adjustable Reflector in Type III position
[LAMP] 400W Venture Uni-Form Pulse Start Lamp, Rated at 41,000 Lumens
[SKTPOSITION] Horizontal Socket Position 5, Street Side Lamp Holder
In 3d softwares it may take a bit of fiddling, but the results are really close to real lights.
[LUMCAT] KH40A-Type III
[LUMINAIRE] KH40 with Adjustable Reflector in Type III position
[LAMP] 400W Venture Uni-Form Pulse Start Lamp, Rated at 41,000 Lumens
[SKTPOSITION] Horizontal Socket Position 5, Street Side Lamp Holder
In 3d softwares it may take a bit of fiddling, but the results are really close to real lights.