Baking Foilage Lightmass taking AGES.

I made a simply grass and painted it with foilage tools. I have only around 1,018 instance count with lightmass resolution of 8. Its taking like 10 minutes to rebuild preview lighting. I have only a directional light and a landscape of 20 x 20 size. Is there something I’m missing?

Lightmass can take a while to build, especially with a lot of objects in your scene that need to be calculated.

You can improve this by using a lightmass importance volume around your playable area.

Decrease the lightmap resolution to 4 or 2 for the grass meshes you’ve painted.

Disable cast shadow for the grass painted foliage. Typically grass will not need to cast a shadow. This will not affect it’s ability to receive and bake shadows.

System specs can play a big part of this as well especially depending on the amount of RAM and processor you have.

As a reminder as well, large worlds are not ideal for baked shadows. While this can work, it can be a very heavy process building lighting for larger scenes/worlds especially if there is a lot of objects that are casting shadows. This is why a lot of open world kind of games use Dynamic lighting.

I hope this helps.


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Thanks for the answer! I decided to not bake lighting on the grass at all. Making it dynamic looks so much better

No problem. Glad you’ve got a solution that you like. Typically things like Grass and Trees would work better as dynamically lit anyway since in most cases you would want this for swaying leaves, branches, and grass.