I have to import a simple map for my game from Roblox Studio to Blender (because I will need to make a thumbnail for the game in Blender). I use Blender 2.80
My map is a model (I grouped it), I right click the model in explorer → Export Selection… and then I save it to .obj file. But when I go to Blender → File → Import → .obj and I select the .obj I exported from Roblox Studio, the model in Blender starts flickering.
I have tried searching from Google but haven’t found anything.
I can’t open the video file, but the issue is most likely what’s called “z-fighting” (when a render engine is viewing a face that has two or more faces occupying the same coordinates, the engine can’t decern which face to show so it “flickers” between both). The way Roblox exports .obj files is pretty messy and full of duplicate faces (which is normal).
In Blender, in Edit mode, select everything (press A), then press F3 to open up the tools, and type into the search bar “Remove Doubles” (or apparently Merge by Distance, thank you @Dhammapada for correcting me!). This will merge together all vertexes, edges, and faces that occupy the same space.
The other cause I can think of (again, can’t view the video), is still due to z-fighting, but it’s because separate faces of different objects are overlapping, in which case you’d have to manually move them each or join them depending on the situation.
Try the first suggestion and if it’s still an issue, try the second. If neither work, send more screenshots so we can figure it out 
Yes, removing some faces helps a lot. Thank you!
