I cannot select the lighting maps which I produced in 3ds Max. The right hand side pane shows the other lighting channels for the object but they are greyed out and not selectable. In the object pop-up window, the other UVs are selectable from the drop-down menu but the selection always reverts.
The tested object is a simple wall section created in Revit 2016, which was meshed and given unwrapped UVs in 2 channels using 3ds Max 2016.
Please find attached an screenshot with the unselectable UV channels on the right hand side.
Ok thanks.
So the ability to use the other light channels whose UVs were pre-made in 3ds Max is controlled by selecting “movable”.
What is still don’t get is why the overlap error showed up during building from static mode since the UV maps didn’t show any overlapping.
I might be missing something in your description, so if I miss something feel free to correct me.
Lighting Channels only work with movable Actors in UE4, which do not require or use lightmapping for static light builds. So that really shouldn’t be an issue unless you’re setting the lighting channels and then setting it back to static, which will not work since baked lighting is not taken into account for static lighting bakes.
Couple of things to check regardless.
Open your Static Mesh in UE4 and under the Settings > Lightmap Coordinate Index make sure that it is set to 1 (typically the default UV channel for lightmaps) or whatever your UV channel is for your lightmap. You can check this by using the UV button in the toolbar and then using the drop down to check the individual UV channels for which one you want to assign as the lightmap UV.
When you build lighting, there will be an initial warning listed for lightmaps needing to be rebuilt, but after lighting finishes there shouldn’t be anything listed that doesn’t have overlapping UVs or other issues. If there is an actor that has overlapping UVs it should indicate here which one it is and it’s just a matter of checking that the correct lightmap UV is assigned and that the UV islands are contained within the 0,1 UV space.
If there is still an issue post some screenshots from the Static Mesh Editor with the UV channel displayed in the viewport and the setting for Lightmap coordinate index visible.
Not to necro an older & answered thread, but since I ended up here looking for a solution I figured this might be helpful to others too: it seems that in at least 4.15 you don’t need to set your light to Movable, you can get away with using Stationery. Also, your actor will work fine with it being set to Static. Tested this on a Plane with a Directional Light under 4.15.2. The directional light was set to Stationery while the plane remained at Static.