## Area lights with variable directional light

Discussion related to the implementation of new features & algorithms to the Core Engine.

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### Area lights with variable directional light

I have found an increasing need for area lights with a more directional light beam. Not as directional as the laser though. Perhaps a setting so the user could change the spreading of the light beam from what it is now to a more direct beam. Like a spot area light. Would it be possible to add something like this to the area light without much work?

With ies profiles you can get more direct light but I find them a little difficult to work with. You have to go through a lot of them until you find one that works.

Piita

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### Re: Area lights with variable directional light

Piita wrote:I have found an increasing need for area lights with a more directional light beam. Not as directional as the laser though. Perhaps a setting so the user could change the spreading of the light beam from what it is now to a more direct beam. Like a spot area light. Would it be possible to add something like this to the area light without much work?

With ies profiles you can get more direct light but I find them a little difficult to work with. You have to go through a lot of them until you find one that works.

Distant infinite lights have a spread angle (the parameter is named theta ,default value is 10 degrees), you want the same feature for triangle lights, it shouldn't be hard to add a theta parameter for them too (default value 180 degrees, the current behavior).

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### Re: Area lights with variable directional light

oh, yes... theta for Area lights, please

also you can make yourself a dozen of IES profiles with IES generator 4 to have them always at hand for any occasion & any other engine supporting IES
burnin

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### Re: Area lights with variable directional light

I'm working on theta support, this is a cornell box rendered with a theta of 30 degree:

I'm considering to add a linear fall off parameter too.

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### Re: Area lights with variable directional light

That is excellent! Thank you

Piita

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### Re: Area lights with variable directional light

I added the support for Material theta parameter:

Code: Select all
scene.materials.Light.type = mattescene.materials.Light.kd = 0.75 0.75 0.75scene.materials.Light.emission = 10. 10. 10.scene.materials.Light.emission.theta = 15.0

Recursive Materials (Mix and GlossyCoating)

A special note about recursive materials: the theta value of the "root" material is always used (i.e. the one defined in Mix or GlossyCoating). The complexity of supporting recursive theta definitions doesn't look worth of the utility (i.e. nearly zero) to me.

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### Re: Area lights with variable directional light

Fantastic! Thank you

Piita

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### Re: Area lights with variable directional light

I guess the default value of the theta parameter is 90?

B.Y.O.B.

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### Re: Area lights with variable directional light

B.Y.O.B. wrote:I guess the default value of the theta parameter is 90?

Yup, it is.

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### Re: Area lights with variable directional light

Ok, I added support in LuxBlend (and description to LuxCore_SDL wiki page).

For users:
You will need the latest LuxCore binaries, e.g. from the binary sdk: viewtopic.php?f=30&t=13329&start=20#p126536

B.Y.O.B.

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