Best way to recreate a real light fixture

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Hello Everyone,

I am currently working on an archviz project in which I would like to realistically recreate real world light fixtures. I have made accurate models of these fixtures and bulbs, and I have the .ies light profiles for each of them. My question is how to best recreate each light given that some are linear lights, some are spot lights, and some are simple bulbs, and I would like to have the bulb mesh appear to be emitting the light. Do I place the light instance that uses the .ies file inside the bulb mesh, which I then make emissive/transparent? I have attempted this strategy with mixed results, with the main issue being that the .ies profile’s intensity does not seem to match the actual intensity I would expect from the real fixture.

As an example here is a point light replicating a linear light using the correct .ies file for this fixture, using the .ies intensity, with an .ies scale of 1:

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This is obviously too bright. I am unsure if the intensity scale is not working or the conversion between the .ies lumen output isn’t converting to candela, or if there is some correction factor I need to implement. This room is typically lit correctly when I use regular lights and sky lighting.

Here is another example, this time not using the .ies intensity, instead using an intensity of 160 Candela (max):

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If I don’t use the .ies intensity and instead adjust the intensity manually, it is too dark even at max intensity.

In any case, this problem seems to persist no matter which .ies file I use, or if I use rectangular or spot lights instead of point lights. I’d like to know if there is a fix for this problem other than adjusting the intensity scale.

Thank you all very much.

2

Adjust the exposure. The light intensity is correct, your exposure is what is set wrong.

A light can appear to be non-existent or as bright as the sun depending on where you set your exposure.

Here’s an example of the same light at 4 different exposures:

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Thank you, I had been adjusting the exposure as a way to fix the issue, the exposure I had set it to was for when other lights were on in the room and when the sun was shining through the window blinds. This does fix most of the problem, but it seems that I will have to adjust the .ies intensity scale for each light to get all of the lights to work at the same exposure level though, or perhaps use multiple post process volumes. This is only a test stage to work out the issues with the lights.

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This is why auto-exposure exists. So that you can get realistic relative intensity between lighting situations without having to manually fudge all of the lights to fit a fixed exposure. Manually adjusting all of the lights to fit in a fixed exposure also will never produce realistic results, though for some projects that may be acceptable.

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Thank you, its working a lot better with auto exposure.

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