''Real'' Lighting in unreal engine

[Arkiras]

@iamgrunt

But is there anyway in unreal engine to make a lighting setup that would phyiscally correct, So you can be sure that is actually how the house would look after being build.

It will not be perfect

@iamgrunt

But when it comes to outside lighting. The only thing with real units seems to be directional lights. while skylight seems to only have a unitless intensity.

Assuming you use the SkyAtmosphere system (which you should) then the intensity of the skylight is managed for you based on the position/intensity of the directional light and the scattering parameters of the atmosphere. The SkyAtmosphere docs has a section at the bottom in “Additional Notes” that describes the setup for a physically based result.

@iamgrunt

And the second issue is the post processing. I have been reading/watching abit on it. And I read alot of people saying to disable auto exposure ( set to min 1 max 1 ). Would this be the correct thing to do or Do I need to properly use auto exposure to get a realistic result for a walkthrough.

Definitely not the correct thing to do. Your desired exposure depends on the amount of light in view, and a fixed exposure value of 1 is almost certainly not going to be a good choice for most scenes, especially not ones with plausible sunlight intensities.

You need to set your exposure, but you don’t necessarily need to use auto-exposure to do it. You can manually set it (what you described is effectively manually setting the exposure to 1). However I think if you spend enough time working with lighting you’re going to realize that auto exposure is a critical tool in projects where the viewer has free control over the camera.

That being said, manual exposure can work if there isn’t too much variance in your lighting.

Some general advice:

• Make sure you enable “Extend Default Luminance Range” in your project settings.
• Use the SunSky plugin, this comes configured out of the box as physically based, and gives you the ability to use a real location and date/time so you don’t need to guess where the sun will be for a given time of day.
• Unreal 5 has local exposure and it’s really nice. I’d recommend upgrading to UE5 when it comes out.