UE4 4.7.5
I want to use a translucent material for animated shorelines, but at the moment I have a problem with the lighting in combination with RayTracedDistantField Shadows. As soon as the translucent material enters the area of the DF shadows the surface that should have been lit becomes unlit.
I was able to reproduce the observed behaviour in an example scene. The scene contains 6 Cubes. 2 Textures ( White & Checkerboard ) and 3 Blend Modes ( Opaque, Masked, Translucent ). The rotation of the directional light source is set to 0,-45,0 so the scene is lighted from top. The “Translucency Lighting Mode” is set to “TLM Surface”, so the lighting is expected to be identical for all cubes, but as soon as the cube enters the distance between 1000 and 2000 ( Dynamic Shadow Distance and DistanceField Shadow Distance ) the top surface of the cubes with the translucent material become unlit. Even when you leave the range of the DistantFieldShadows ( > 2000 ) the surface stays unlit.
You can see this behaviour in the example scene, just move the camera a little bit away from cubes and toggle the DistantFieldShadows of the LightSource. It doesn´t seem to be an artifact of shadows, because even when the casting of shadows is disabled in all actors the surface stays black.
Do I have to adjust other settings in the material / actor or is this a bug?
[Example Project][1]
Sorry for the delay.
Your scene description is very detailed, but I must be missing something because I was not able to get the translucent cube to be shadowed (or maybe behavior has changed in latest).
Scene settings:
- Directional light set to movable, dynamic shadow distance 1000, ray traced shadows enabled, distance 2000, rotation matching yours.
- Translucent and opaque cubes, BaseColor .5, opacity 1
At this distance the ray traced shadows are active for both, which is why the translucency has a shadow (this is actually a different bug, ray traced shadows ignore the blend mode of the material)
After syncing the dev branch ( 4.8.0 ) I couldn´t see the black surfaces anymore. Seems to be fixed between 4.7 and 4.8,
Hi,
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Thanks!
Hello Daniel,
have you set the “Translucency Lighting Mode” to “TLM_Surface?” I have added 3 cubes to the scene that use translucent materials with the 3 different Lighting Modes ( and disabled Cast Shadows for the actors ). TLM_Volumentric Directional and TLM_Surface seems to have unlit surfaces on top of the cubes.
I used base color 1 and opacity 1, but even then the cubes in my scene are a lot darker than yours. Do you have placed additional lightsources? I attach my updated example scene. It is based on the blank blueprint template.
[Example Project][2]
Yes, sorry I forgot to mention that. I tried TLM_Surface and the other modes on the translucent material and didn’t get the black with any of them.
I used base color 1 and opacity 1, but even then the cubes in my scene are a lot darker than yours. Do you have placed additional lightsources?
I think that was from baked lighting, there were no other light sources
I loaded the example scene and it worked fine on my end, none of the cubes were black. So either this has been fixed in latest, or is something specific to your machine. I tried all the engine scalability settings and none of them make the translucent lighting black so it’s not that.
We have tested this project on different machines with 4.7.3, 4.7.4 and 4.7.5. I will now sync the dev branch of the engine and try it with that version.
Thanks for your help.
Thats ok for me. Please share the informations.
