Indirect Lighting Cache and Foliage

Ok, I’ve spent the day going though all the documentation on lighting and have learned a good bit. I found out that Lightmass makes an Indirect Lighting Cache for dynamic objects. I have been doing tests with foliage using that an it seams that each foliage type can only reference a single sample point. See the images bellow as to how adding foliage in a different lighting affects that entire group. Is this the expected result? If so, how can I solve the problem of trying to get the foliage to correctly respond to indirect lighting?

Images aren’t imbedding…

Hi Oxygencube,

This is a known and reported issue with UE-20029. Currently it’s on the “To-do” list. There is no set time frame for when this will be addressed at the moment.

I’ve added this post to the ticket and will update once I know more or there is a fix.

Thank you!


Hey -

We’ve been experiencing the same issue. Since our landscape chunks are fairly large, it ends up with very abrupt transitions. To solve this, I was able to add a flag to the grass which disabled static lighting for certain grass elements. It means that it doesn’t pick up any static lighting, which is far from ideal, but solves the abrupt lighting transition issue.

I also tried using the IndirectLightingCacheQuality ILCQ_Volume setting, but it wasn’t clear without more digging how to make this work – a quick test of setting the bMobility to Movable didn’t seem to change anything.

I’m happy to share our solution. It’s only applicable in limited scenarios, so I’m not sure creating a pull request is the right answer here.


This has been assigned to an engineer and is on the “To-do” list to be looked into.

I’m not sure if something that works in limited scenarios would be as helpful, but I can always add the information to the ticket in the event there is something useful there to pass along to the engineer.

I have the seem problem with grass & folliage .

All Foliage in my scene is in movable but the result is not correct. i dont know this. Can u help me to resolve this pb, thk u

Hi all
I also have to find the way to fix this problem , So far I still headache , My foliage all in scene have been set to “movable”
then just only this tree (in the images) brighter than the other. I had try to rebuild the scene many time but still have no clue how to fix this ,
Would be appreciate if someone provide resolution.