However, on UE4, on the lightmap density viewmode, I get different colors of the lightmap densities. And this is happening quite often and screws up the lightmap densities as I can’t get it all consistently even.
And also, I am changing the lightmap resolution, that is how I notice this issue, because while most of it will be green, some parts will end up being blue or in bad cases red, because it’s uneven. Like in the model I posted the question, where it is all one model, but some parts are green while the lower big beam is still blueish.
just relaxing doesn’t result in even scale and texel density.
You need to normalize the uv-islands(rescale elements button in the uvw unwrap does that)
Additionally, you might want to make sure the distance between uv-islands is correctly set up, you align most of those uv-islands so they are aligned either horizontally or vertically, and that the padding on the edges of the islands as well as the edges of the 0-1 space are correctly dont for the lightmap size you want.
you might also need to adjust the lightmap sizes of the meshes after import, either 16,32,64,128,256,512,1024, etc.
Until everything is around green-ish in color.