Sketchup/Indigo light mesh/material behavior guide

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Yiqin
Posts: 40
Joined: Sun Nov 10, 2013 6:08 pm

Sketchup/Indigo light mesh/material behavior guide

Post by Yiqin » Wed Sep 29, 2021 10:43 am

Was looking for light setup and behavior to help me with accurate light planning and couldn't find what I wanted in the manual nor in this help forum so I'm posting this as a supplemental guide for setting up lights including IES. Doesn't cover everything. The info below may be specific to indigo emissive material/mesh light behavior in sketchup I don't have time to check it all in 3ds max.

Indigo version 4.4.18/skindigo 4.6.01


Emission Scale/light output:

-For single mesh lights that are made of a component or group the emissive Material will treat Emission scale value (lumens/lux/candles) as a per light value
(example: each component or group that uses the same emissive material will have the same emission scale/output)

-If the emissive material is applied to multiple unconnected surfaces (all of which are in or outside of a group/component) The emission scale/light output is divided between each unconnected surface or another way of putting it is connected or not the emissive scale is evenly distributed across the mesh.
(example three unconnected quads in the same group will each get 1/3 of emissive scale/light output)

-In the case of an emissive material with an IES that is on multiple unconnected surfaces (in the same group/component) it appears that each individual surface exhibits the same IES profile only with the emissive scale/light output divided among them.


Light Mesh:

-A light mesh can be more than a simple triangle (can be ngon/subdivided/circle/multiple quads and doesn't matter if mesh is smoothed or not) without changing the IES or emission scale BUT for best results an IES light mesh should the same approximate size as the lens/light emitting surface of the fixture the IES represents and be planar. Light will be evenly emitted from the mesh and an over sized mesh will distort the IES light distribution.

-A non-planar/3d mesh will change an IES's light distribution as well and there won't be any warning from indigo.

Please feel free to add, correct, or expand the above

Ewie
Posts: 4
Joined: Thu Oct 22, 2009 2:02 pm

Re: Sketchup/Indigo light mesh/material behavior guide

Post by Ewie » Tue Apr 09, 2024 9:01 am

Good tips there. Have you figured out how to change the orientation of an asymmetric IES mesh?

Yiqin
Posts: 40
Joined: Sun Nov 10, 2013 6:08 pm

Re: Sketchup/Indigo light mesh/material behavior guide

Post by Yiqin » Thu Apr 25, 2024 12:15 am

Ewie,

I'm not sure if its the same problem you are having but a long time ago I had an issue with the wrong IES type (unsupported) and eventually found a program that would translate IES files to other formats. Unfortunately I no longer remember the details or the program but a quick search revealed a few possibilities. I feel like all the IES files I've picked up from vendors last few years have been the right/supported type for indigo (types being A, B, C - seems like maybe A was the unsupported type though I don't really remember)

A tool like these might also allow you to change the default orientation of the IES map, though that would be rather annoying to deal with externally- going back and forth to get exactly what you want for each light.

It sounds dumb, and you've likely already tried this but maybe try to make a light as a component then simply try rotating your light component in model. Do test render and rotate and try another test render? This kind of test will also let you know if Indio is accurately or consistently representing asymmetric IES files...

Sorry I'm not too much help here generally I deal with spotlights/floodlights that are symmetric (exterior lighting for freestanding artwork). The Developer is putting most of their attention on substrata these days but you might be able to get a response through the support email.

Good luck!

Ewie
Posts: 4
Joined: Thu Oct 22, 2009 2:02 pm

Re: Sketchup/Indigo light mesh/material behavior guide

Post by Ewie » Thu Apr 25, 2024 4:40 pm

Thanks for the feedback. I've tried changing orientation and re-rendering to no avail. I'm a lighting designer, and I work with IES files all the time. Type C photometry is the one you're thinking of and is the most common. Type B is rarely used anymore but was mainly used with streetlighting and floodlighting. I don't think I've ever used type A in my career. The issue, I think, is that the IES file is linked to the texture/material rather than the surface/object.

The only workaround, sort of, is to edit the IES files for various orientations and apply them to separate textures/materials, but that's an awful lot of work and very cumbersome.

Not getting responses from email either for some reason, including a recent one when I asked about compatibility with SU2024...

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