Hi. I'm trying to upload a file created in Sketch Up, then saved in Meshlab, but I keep getting the Non-Manifold error. I have saved it in .stl and .dae extensions. Now I know there are lots of questions regarding this same topic, I have gone through all of them and as far as I know I have done all recommended. But I keep getting it. The error may be there, but I just don't get it. Could I get someone's advice so I can keep uploading? Thanks!