Directional Area Lights

I have a couple of questions about the new Area Light Spread setting as I am incorporating it into the Physical Lights units of my Photographer addon.

  • The spread value conserves energy, meaning using a narrower spread will focus the beam and make it brighter. However, this is not how the Spotlight Size (cone angle) works, does it make sense to have two different behaviors? I see that you wanted to give the option but it’s not what has been committed at the moment.
    I will support both depending if it’s lumen or candela anyway, but I am curious about this choice.

  • Spread is not supported by EEVEE and breaks compatibility between the two engines now, especially because of the brightness difference. Will it be added before 2.93 release?

Best,
Fabien

It makes sense to have the option for both, it just was decided this was not a requirement for the patch to be added.

Probably not for 2.93.

It’s not obvious how to do this in realtime, at least I’m not sure how you’d adapt the Linearly Transformed Cosines method to this. But that shouldn’t hold back features in Cycles.

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hello Matteo thanks for the new feature very useful.

I have a question regarding using area lights as a projector.
I tested it with a video file and it works. However currently in order to get a sharp projection on a wall, the area light has to be close to the wall like this:

As soon as I move it away the projection gets blurry.

My guess is that it has to do with the current minimum of 1 degree spread?
Would it be possible to have the option to set it to 0, in order to use the area light as a projector?

Hi, it is already being proposed, discussed and (I guess) planned

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ok thanks. Can you please share the link to the discussion?

It was mentioned in the rendering meeting notes from 2021-04-27:

Link to the topic:

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