Building light - overlapping uv's

Development Rendering
1

hey guys,

i made a house and put it into ue4 and now iam at the stage to build light. i presed “build light only” with preview settings. now i got the problem that i got the message "overlapping uv’s. i located the problem area but i dont know how to fix it.

i have 10 different wood elements for the house. i unwarpped and baked these 10 elements together and they are placed on one uv space because they are all out of wood - got a tileable texture for it. after the baking and texturing prozess i detached all of these 10 different elements and placed them at the house. i reused these 10 elements several times at the house and made always a copy of the piece i need and placed it where i want to. exactly at these parts i’ve overlapping uv’s for about 30 %. is it a problem to copy parts even if they are not attached?

for export i choosed .fbx and just marked all pieces with a selection and exported all elements als one fbx out.

My questions are:

  1. can i export as many not attached objects als one .fbx?

  2. how can i fix the overlapping uv stuff

  3. is it possible to have no problems even when i copy elements?

Thanks

2

You have to differentiate between your first UVset for texturing and your second UV set for lightmapping. The second set has to be non-tiled and without overlaps, so just copy your uvs over from your first uvset and fix the errors in uv channel / set 2.

concerning your questions:

  1. Yes you can export many separate objects with one fbx file. Just make sure that you dont use “Combine Meshes” when the import settings come up. If you combine then, you also combine their UVs and they are overlapping afterwards.
  2. See my text above, UVset /uv channel 2 needs to be non-tiled and just free of overlaps, it does not affect your texturing work.
  3. Yes, possible without a problem

In generel, check the documentation about Lightmaps and unwrapping your meshes. Seems that you are quite new to this kind of workflow.

3

ok thanks sir,

what would be the best way:

  1. check the 2nd uv channel with the 10 wood elements directly

or

  1. select all objects after placing them and then check the 2nd uv channel?