Building light in 4.6 requires a lot more time than 4.5


after switching from UE 4.5.1 to v4.6.1, the build time for lighting of a scene increased from 3 minutes to 38 hours!

As it’s a landscape with trees, I guessed that the new “Static Lighting on Foliage” feature was responsible for this. So I reduced the “Lightmap resolution” of instanced foliage to 4, reducing the build time from 38 hours to 16 minutes.

Any further hint to return near the 3 minutes of v4.5.1?

If it could be useful to others, I solved reducing the “Light Map Resolution” to 4 for all meshes used by the foliage tool:

  1. tool "Foliage"
  2. tab "Select"
  3. for each listed mesh:
    1. "Show Instance Settings"
    2. set "Light Map Resolution" to "4"