I use Collada files from SketchUp.
When I import them into Blender some times import goes as intented but sometimes it imports only part of it.
Here is for example you can see this chair. The right one is imported as Collada (DAE), and the left one is the same .DAE file, but I put it trough online mesh converter and imported as OBJ.
Why can it be and how to fix it?