ies lights

because UE4 is used a lot for architectural simulations I’m trying to simulate real architectural lighting with photometric data.
I noticed that is not possible to create asymmetrical lights and it’s very difficult to orient ies lights in space.
Imagine to light a museum with hundreds of pictures and sculptures. You can’t orient your lights picking the target point, because it doesn’t exist in UE4. The camera light positioning is a trick and it’s a time consuming process.
Recently wall washer lights are used as emitters to wash uniformly entire walls or facades.
In UE4 is not possible to see the spatial distribution of a ies light.
I understand that UE4 was born for games but we, architects, want to build our virtual spaces closely as much as possible to reality.


Hey gabrielefx -

Currently the engine simulates IES in the editor. The IES profile which is assigned to the light fixture in the editor is actually not treated as math (as it would be in a non-real time rendering application) at all but in fact converted to a representative texture file which is then added to the light, in a similar way a light function is applied but far more performance friendly. I have placed a feature request in for representing the spatial math present in the IES file, but I do not see this happening quickly as it would be a considerable performance issue that would have to be overcome before it can be represented.

As far as not being able to use asymmetrical lights, do you have a particular IES profile that is not working for you? I just recently used a florescent tube IES profile in a project that was in fact asymmetrical about the YZ and XZ planes, it happened to be symmetrical about the XY plane. If you could upload the IES file I would be happy to take a look at it.

Thank You

Eric Ketchum


are there any updates in the meantime? The topic is pretty old.

kind regards