[Bug] Rotating movable static meshes lit as if static screws up their lighting

Hello all,
I just discovered an odd bug in our project where we play with movable static mesh actors which have baked lighting (Light as if static).

If you move them during play, everything seems fine.

However, if you rotate them a strange issue occurs. Adding rotation somehow darkens the mesh. Running up to 180° rotation, the mesh becomes nearly complete black. Towards 0° the mesh returns to its original lighting.

I also made a gif to illustrate the issue. It’s briefly interrupted at 180°.

http://i.imgur.com/6Jjoaf6.gif

This bug was reproduced as follows:

  1. Open a new/blank project (i chose top-down example project)
  2. Set some mesh actors to movable and light as if static
  3. Add somewhere in BP a continous rotation of the meshes (e.g. level bp → tick → addActorRotation)
  4. Bake the lighting of your scene
  5. Start playing and observe & wonder…

Hi LeFxPete,

I’ve entered a ticket for this because it looks like the volume light samples aren’t being honored for the movable mesh when it’s rotated. The ticket is UE-20233.

I’m not sure if this is actually intended behavior or not in the code, but it will be reviewed and I’ll update you once there is any progress made on the ticket.

Thank you!

Tim

Thanks alot for your fast response. I’m curious about the outcome.

Hello. Any progress on this bug? I have the exact same issue in my project as well.

@MasterM

This was marked as “by design” and will not be fixed according to the ticket.

Thank you for your reply. Care to share any details as to where to look in the engine code so that I can “fix” it myself?

The ticket doesn’t include any of that information and I’m not a programmer. I’m not sure exactly what file this would be in in the source, and unfortunately, I don’t have the spare time to dig into the code and locate where this could be set.

If you do get a “fix” for this, I would encourage you to submit the pull request via GitHub to help anyone else as well.

Sorry I couldn’t be more help.

You can fix this by disabling “use lightmap directionality” in your material settings

This obviously is not a bug. The whole point of setting a mesh to have “static” lighting is to allow the engine to precompute a bunch of stuff so that the game doesn’t have to at runtime. There is a direct tradeoff: you lose flexibility and some runtime memory and you gain more processing cycles in your game.

If you want to be able to rotate meshes without them looking bad, don’t set them to be static and don’t use static lighting on them.