Ask Epic Anything: Lighting in UEFN | August 24, 2023 at 11AM ET

[jon_eg]

@ImerzaChristo

At Imerza we create digital twins of real-estate and industrial applications. Adding a lighting control feature for inside a condo unit while closing the window shades is on our roadmap. We would include dimming as well as a selection of different color temperatures. While doing this in a general and high-level way is achievable, I’d like to learn more about best practices to create extremely accurate visualizations of existing lighting products.

Hi, this sounds like fascinating work! I just wanted to point out that this AMA is focused on Unreal Editor for Fortnite (UEFN). I’m not sure if you are interested in doing this work in UEFN, or regular Unreal. UEFN currently has a more limited feature set than Unreal, so the answer might be different depending on which you are considering.

@ImerzaChristo

IES: Unreal allows for IES file imports but you have to match it with one of the limited form factors such as a point light or omnidirectional. How would a tape light or linear fixture IES file be accurately applied to one of the existing profiles or is there another way?

It looks like Rect Lights (aka area lights) in Unreal/UEFN do support IES profiles, but I don’t know if it would apply in a physically accurate way for a long tape light for example. Large or long area lights in general have limitations in real-time renderers since they are difficult to cast accurate shadows from in real-time.

@ImerzaChristo

Lighting designers and architects rely on lighting calculations to trust that simulations are accurate. The industry standard has been AGI32 for years. Are there plans to be able to perform lighting calculations in Unreal?

I am not familiar with AGI32. However Unreal lights do support physical units – lux/lumens/candelas depending on the light type. There is more documentation about it here: Using Physical Lighting Units in Unreal Engine | Unreal Engine 5.2 Documentation