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big issues when mimicking the real world with physically accurate Lighting and Camera System.

. recently i was doing some lighting research in UE4 . and i have notices some major problems when trying to mimic real world values. here i will be showing 2 projects To discuss this issue. to be clear the comparison is mainly about how physical accurate Lighting values will affect both the Lit Mode and Path tracing Mode.

-the First set Images shows a simple interior Scene with this Lighting Setup :

1- Directional light with intensity 82000 Lux
2- Hdri with intensity : 20000

-the camera setup :
1- shutter speed : 100
2-Iso : 100
3- Aperture : 16

As you can see the Lit mode is fairly nice but when i choose the path tracing Mode the image gets very incorrectly shaded . also some actors never respond correctly to real world values such as fog actors and Bloom.

  • the other set of images are for a simple exterior scene With this Setup :

1-Directional light : 95000 Lux
2- Hdri Intensity : 35000

-the camera Setup

1- shutter speed : 100
2-Iso : 100
3- Aperture : 16

as you can notice the first image looks Nice and i switch to path tracing mode the scene gets completely dark.

side notes

1- when using such setup with interiors with some reflective surfaces the roughness of the scene gets very low and seem like a very reflective surface and objects are shading very incorrectly.
2-when such setup with unlit mode everything Becomes white.
3-bloom only works when it is set to standard. when it is set to convolution the scene shades Completely incorrect.