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Creating a visible Spotlight

Posted: Tue Jul 10, 2018 5:05 pm
by edwardtremethick

I am wondering how to create a spotlight in Sketchup, that is then a visible light in Skindigo when rendered. I have emailed the Indigo Team, and they have sent me the following information and also referred me to ask here.

"You need to have a participating medium (e.g. SSS medium) for the light to scatter in." - How do I do this/what does it mean? Is it done in Sketchup, or in Skindigo?


"You also need to form the light into beams in the first place. You can do this by modelling a parabolic reflector with a shiny metal."
How can I model this parabolic reflector?

Thanks. Edward.

Re: Creating a visible Spotlight

Posted: Mon Jul 16, 2018 6:02 am
by yonosoy
Hi Edward.

First, use a geometry (a simple box could be perfect) for the SSS component. The box must take up your scene. Apply a specular material with IOR=1 and an amount of SSS. This is a simple example of the material. You have almost one example more in the database. The concept is that there must be some dust in the ambient (or vapour...).
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Then you need to modell a reflector. A parabolic one is the best. Here you have some clues of how to do it in Sketchup. If you have problems to do this, try with a cilinder with a tap opened and oriented as your desire. Give to this geometry a shiny metal material to reflect.

Once this is done you need a third geometry for the light (a little sphere could be right). Try a simple polygon with an IES profile (this is more like a trick). Give to this geometry a desired emitting material. In this video is explained the parabolic concept, so you can place the light correctly in the parabolic reflector.

In this way you will be able to see the volume light as you desire.
If you have some kind of problem I will try to help you more and give you a modelled example (maybe in a days).

Good luck, hope this clarify something.

Re: Creating a visible Spotlight

Posted: Sat Aug 11, 2018 3:13 am
by edwardtremethick

Thanks for your response. Very useful. I am still confused about an SSS medium. As I am not sure how to set the amount of "SSS". I am not sure if I am setting it correctly. Are you able to show me the parts of the Skindigo Material Editor that I need to change?

I haven't got around to doing much yet. But I should now be fine with making a parabolic reflector. Thanks for the Youtube videos.

Re: Creating a visible Spotlight

Posted: Tue Aug 14, 2018 12:10 am
by yonosoy
Hi Edward.
Not a Sketchup user.

Setup a specular material with IOR=1.
Absorption, uniform spectrum; play with the values. Start with 0.0005.
SSS, uniform spectrum; play again. Starts with a value of 0.003.

Glad to hear that the info serves for your parabolic reflector.

Re: Creating a visible Spotlight

Posted: Tue Aug 14, 2018 3:36 am
by Eneen
You can also simplify light if this is not closeup render to flat plane (circle)+ies. Indigo is really great in that regard, you just assign material and get IES profile regardless of emitter shape, so you can create led stips and other non-omnidirectional lights.