Hi,
To make sure not to miss anything I’ve produced this unlisted video to show the issues:click here for the video
Hi Pino,
There are a couple things I could suggest that would help you out in this area.
Combining more than a few BSPs and converting them into static mesh will not yeild expected results with lightmaps without exporting to an external program for cleanup.
I noticed one thing in your video immediately that will show you the rough results of lightmapping.
When the lightmap is generated using the create static mesh from brush tool you’ll need to manually assign the lightmap to it’s coordinate index in order to use it. By Default it’s still using 0 which is for the texture UV.
You can correct this by finding the Lightmap Coordinate Index in the details panel on the right when you open the mesh. Change it from 0 to 1.
Next you’ll want to up the lightmap resolution above 64 for an object this size. The box you were showing the 64 in is the place where you can generate that size lightmap. This is not the lightmap resolution setting that is affecting the Lightmap UV directly when you build lighting. You’ll need to set the resolution under the Static Mesh settings > Light Map resolution.
To go over why combining this many meshes doesn’t work well I’ve got some images below showing the different generated Lightmap resolutions and as you will see the UVs are broken up into smaller piece which does not give you great control over having good lighting this way. This is why you would want to use an external program for your lightmap UVs. BSP’s are primarily meant for basic blocking out of levels and not as a modeling solution.
Lightmap Resolutions:
64
128
256
Here is the final result when I build lighting and the artifacts that will happen without exporting to clean up in a 3d modeling software.
I know this isn’t the answer you were hoping for. Alternatively, using smaller meshes rather than all the selected BSPs will give better results. For example, using a single wall with the door subtractive brush would be better for a good lightmap.
Tim
Hi Tim,
Thanks for your answer. Indeed my hope is that the mesh generation algorithm would be fixed in the feature because as it is is not usable, hence my bug report. If we can indeed export a static mesh out of BSPs then we should expect a proper result, and that is possible indeed… there are a few bugs in that algorithm so I rather not have the opportunity to export a mesh than having a messed up mesh 
Cheers,
Pino
This is the first build with it in there. So there are some issues indeed that will be addressed as the feature is more heavily used. I’m not entirely sure that you will really see the best results using larger meshes though since the larger your meshes are the less space there is for resolution in the 0,1 space for the Lightmap.
Tim