I have been experimenting with image based lighting (IBL) in UE4 4.22 for an archviz scene using physical light units/proper exposure values.
I am trying to get the skydome to contribute to the surface luminance (measured using the pixel inspector) of a white card by increasing the brightness of the skydome emissive material via a multiply node and scalar value. Use emissive for static lighting is also checked, and skylight is set to ‘SLS capture scene’. Currently there is no directional light as I am trying to test only the hdri lighting.
It’s important to note that I am able to affect the surface luminance of the white card using the skydome by increasing the ‘skylight intensity value’ - however others have commented that altering this value is physically incorrect. I would like to find a way to effect the luminance of the white card using just the material emissive parameter.
I have included images of a white card luminance measured with a skydome intensity of 50,000, one of a white card luminance measured with a skydome intensity of 1000 and a shot of the skydome material (just in case).
Any help or suggestions would be much appreciated