Hi Moritz, yup I do want to a grouping function in addition to the "object name" tagging as another way to organize things, it's just one of those things that I haven't managed to get to yet.

> Are there any restrictions about "SAVE AS - WAVEFRONT (.OBJ)"?

Well, you can't export a sub-object selection, it only will export a complete top level object that is selected. That's for File > Export (short for "Export Selected") which writes only the selected objects to the file.

For File > Save As it will write everything independent from selection. The only restriction there about OBJ format is that it will only export surfaces and solids to the OBJ file, not curve objects.

Which particular object are you having problems with exporting?

If your object is not a closed solid it can be possible that the "outward" surface normals are not in the particular direction that you expect and you may need to adjust a setting in your rendering program to show both sides of objects instead of only one side. That can make it look like you're missing things when only one-sided rendering is turned on for surface objects.

- Michael