External 3D program of course should solve any kind of issues, but that would be unnecessary work for me, because for all my needs UE4 tools works perfectly ok. And I suppose if feature present in engine, it should work without any kind of stange behaviour. Thank you for reply in any case.
By the way, is there then some way maybe to remove lightmap or replace it inside UE4 editor?
It was generated automatically I assume, when I clicked “convert to static mesh”, because I didn’t see any kind of settings for generated lightmap or even notification that it will be generated. Is there a way for some manual setting inside UE4?
As for 3D programm, if I won’t be able to find any workarounds it seems that I’ll have to use it.
After I tried to reduce sides count from several hundreds to several dozens, UE4 managed to create static mesh properly without any issues with lightmap.
Also MrGoatsy thank a lot for clarifying the name of the issue for me. I wasn’t able to find proper info about this, because I couldn’t understand what exactly should I search for. Now with your help I understand the topic “lightmap generation during static mesh convertion”. I searched answerhub and forums for this topic and found out that this was known issue and maybe it will be fixed, maybe not. Anyway for now I found proper pipeline to continue my work, thanks.