Thanks a lot for the effort But after testing those things, including creating a new scene, none of them changed anything in the render results. It may be, because this model actually do not have any LODs (just the main model in all it´s glory), and therefore UE should not even switch to any other LOD or model with lesser polys.
And if anyone want test it, i packed the project into a ZIP. The zip also contains a folder “Import-Stuff”, in which i have stored the original C4D file, a special for exporting to UE prepared file (C4D-Melange, since Melange is a process, that prepares C4D scenes for better import via Datasmith), and the mesh as FBX file. I also packed those original mesh files separatly into my cloud, just in case, that the zip is broken.
This project contains a level blueprint that lets you take screenshots with “P” for 1920x1080 and “L” for 4k, and with 1-3 keys you can switch through the 3 cameras, from which camera 2 and 3 are the imported ones. The FBX didn´t save camera infos, so i just added a normal CineCamera and linked it to “1”
Just some thoughts from me:
As far, as i understand, Lightmaps should not really matter, since it´s pure raytracing with a fully reflective material for the main body (it´s just black, because right now, there is no surrounding to reflect, like a HDRI Backdrop) and a glowing mat for the edges. None of them would require any lightmaps since one just reflects everything, and the other just sends out light, reciving light not required.
Cinema4Ds contains two renders, but both of them are capable of doing all the raytracing stuff, even more than UE can do. The difference is just, which one you choose, since both are optimized for different tasks. The “normal” render is in this case faster, since it´s all supershiny reflections and not much else happening. The other, physical render, would be faster, if all the mats would be very rough/diffuse and if the scene would contain a lot of glass ( -> raytracing glass with bending the rays via IOR, and caustics) or subsurface scatter.
But since those effects would be caused by the actual materials, UE should only got those infos, if the materials are set up for glass or subsurface scattering or are pretty rough and diffuse.
However, i had replaced all imported mats with simple new created test mats, so even those infos should not matter, if they got damaged during import, or got imported with wrong settings.