I also use Sketchup for making my models and it does have some problems. The main one is it can't really handle single or sub-millimeter distances. The core code is designed for (american) buildings and can't reliably go below 1/16". If you are doing very small or accurate models it may be that the STL files are being corrupted when exported from Sketchup.
What I do is create all my models in Sketchup using meters instead of millimeters i.e. if I want a 20mm cube I create it as a 20m cube. This way Sketchup can handle sub millimeters (as it thinks they are actually 1000x bigger) and you don't get rounding errors that prevent things lining up. When you export it, do so as Meters as well. The STL file format does not contain the units info - just the values. So my 20m cube just comes out as '20'. When Cura opens the file it assumes I meant millimeters and everything fits perfectly.
If you already have some models, just select everything and use Scale to scale it up by 1000. Then save it again and export as Meters.
try opening it with meshlab (which is free) and then saving it. Just doing that will repair some errors.
Link to post
Share on other sites