OBJ exports for Blender not importing

Over the last couple of weeks I’ve several exports to OBJ being rejected by blender on import.

I’ve assumed this was due to something I’ve mucked up earlier on in the modeling process (in the past with EI’s modeler that was generally the case, due to usually something wonky I did with a control point on a curve I didn’t catch and then many derivitive operations later it’d fall apart.

In all these cases analyze passed all of them with flying colors (no bad faces etc), so I’d just back up and try again. What I’ve seen thus far generally has been things like chamfers or bevels on solids too close to other edges and that sort of thing.

However in this last case it was simple extruded circles booleaned out from an extruded rectangle that while it did have fairly large chamfers on the 4 corners, they were no where near the booleaned circles. It looked fine, exported fine, yet refused to import into blender.

Going back if I undid the boolean leaving just the extruded rectangle with the edge chamfers, that imported. Going back further and undoing the edge chamfers and redoing the booleaned cylinders imported as well. It was only the combination of the boolean and the corner edge chamfers that caused the issue.

I’m also seeing problems on OBJ exports with an imported object that normally exports fine when imported into a different file. The only difference is that it had been replicated, scaled and placed via place on curve on surface command by points.

I’d projected a curve on surface, divided that, then placed the copies snapping to points on the projected curve. When only these copies were selected for export to OBJ, Blender choked on the import.

I’ve done more or less the same process on other files without incident.

My Library file (just a series of the same object with a simple revolved curve matching the objects profile geometry to use as a cutter, along with a placement point) had worked fine in the past, my only change had been to add a dimension to each copy for easy visual reference by their size.

The workflow is I import this library (an array of the grouped items described above) into the current project, do my placements, then delete the imported library objects, ungroup the placed groups, select the cutters by name, do the boolean subtract, then delete the placement points, select the remaining placed objects by name and export that selection to a separate OBJ file for import into blender.

I’ve more or less given up on trying to export entire models as OBJ as invariably blender will choke on the entire file, so I export in several files, selecting objects by name and exporting like parts per obj file, then importing those one at a time into blender so at least I know what didn’t fly.

Am I just approaching this incorrectly or is there something wonky on the OBJ export? As mentioned early all the analysis tools show everything to be good as far a rhino is concered, yet more often than not I find at least on of the exports that will refuse to import.

Hi Mark - can you post a couple (simpler the better) of objects that make the misbehaving obj files?

thanks,
-Pascal

Will do. Don’t have them with me (at the office) but I can get one up sometime this weekend.

How do I post a file? Will the upload button in the post editor suffice?