[build #1711197 ] Translucney rendered in wrong way in shadowed areas

I have problem with translucent materials. I believe it is connected the the problem with particles I have reported earlier, just diffrent use case this time.

I have WoodBeam, with two materials (one main and one that is simulating corner damage). The second material is simple transparent material with two textures.

I have uploaded sample to the FTP:

Lukasz_transluceny_Test.zip

The mesh is called: SupportBeam_4m_30cm.

The reproduction should be simple. Replace normal DirectionalLight with Movable version, remove any AmbientCube maps that might be present, and leave EnviromentalLight at normal level (5).

This images shows how transluceny looks at this conditions:

Transluceny Wrong

Here is material that is masked instead of translucent. I would expect that trasnlucency will look very similiar just softer:

Masked Correct

Here is more extreme example of how it might end up looking. Again masked material looks perfectly fine here:

Transluceny Extreme

edit:
As for extreme example, Disabling DirectionalMovableLight fixed problem.
The in house lighting setup is composed of various light. 4 Stationary Point lights (their radius do not overlap) few static lights, particle lights, single AmbientCube map.
It seems with combination with DirectionalMovableLight, translucency material (on my wood beams as well as particles), just refused to work properly.
It seems odd because in theory the Directional Light shouldn’t have any direct effect on my interior (except Shadows of course).
Unchecking Affect Transluceny Lighting of course also help and it’s nice solution for my current scene, but I don’t think it is acceptable when we also have outdoor things (like smoke, that would cast shadows).

One possible solution would to define whether the translucent material should be affected by directional light per material level, of diffrent lighting channels, to put objects it, so they are not affected by that light (or more specific whether the trasnluncy of said object should be affected by an light).

Hey Lukasz,

Good news I was able to replicate this issue. The better news is this was fixed and will be included in a future release. For now you will probably have to use the mask option as a work around.

Best Regards,
Ryan

Hey
Thanks for answer, I have also nailed another use case issue, I dunno if that is the same thing, so I just post it here so you might check it. I again uploaded the thing to FTP( Lukasz_Trasnluceny_test_2.zip) it contains map:

Decal_Test_map.umap

The reproduction is very simple. Just check and uncheck various DirectionalLightMovable options, like Affects World, Cast Translucent Shadows etc.
For example after Unchecking Affect Trasnlucent Lighting, part of the meshes are affected directly are turning back (well it’s not completly dark if you zoom enough it will pick some color).
On other hand turning the same option makes the shadowed part to be very bright.

Also unchecking Cast Shadow option change look on bright side of the mesh (on darker too, but it’s more apprent on the bright side), but on other hand unchecking Cast Translucent Shadows have no effect what so ever.