Does anyone know of any limits on file or mesh sizes for exporting to OBJ from Blender?
I have high- and low-poly versions of a mesh that I’m trying to export to OBJ. The low-poly exported just fine, but Blender is crashing after about a minute of working on the high-poly version. No errors or anything - it just suddenly isn’t open anymore.
The high-poly is pretty huge - it’s a detailed sculpt with about 45,000,000 quads. I’ve done other large meshes before, but I can’t remember if any have been quite that high.
I’m on an i7 4790k with 16GB RAM, so I wouldn’t think it’s a resources issue, but of course I could be wrong there.
I’d suspect you ran out of RAM. A quick test of exporting a 32M poly object peaks at over 23GB (computer has 24GB RAM). The file did eventually export successfully.
Check your memory useage when exporting or try exporting at a lower poly level
I see my RAM max out when doing test renders on this high-poly mesh, but even though they take a while to load everything up after the RAM maxes out, it does still eventually render. Is there something different about exporting that would make it crash instead of just taking longer to complete like rendering seems to?
It has to write all of the vertex data to file for the export, this will take a while, and may even require your system to write and use a swap file when the RAM is depleted. I haven’t exported and obj that large before, but I do know that a 3 million poly object can take several seconds sometimes. I can only imagine 45 million quads. If you are using Windows, there is a timeout when Windows will white out a screen and think the program isn’t responding, but in the task manager it’s still crunching away and taking up resources. Is this what is happening?
No, eventually Blender would just quit, no errors, no white screens, nothing. I would just suddenly be on the desktop.
I was playing around with page/swap files to give it some extra resources, but even giving it about 180GB total (16GB RAM, ~64GB SSD, and ~92GB HDD) wasn’t enough - it lasted much longer before quitting Blender suddenly, but still never finished.
Those page/swap files are much slower than normal RAM, though, so that might be the problem. I’m just planning on getting more actual RAM and trying again at that point.
New results - upgraded to 32GB of RAM, and it still didn’t export to OBJ. It just crashed after a couple of minutes.
It seemed to fair better trying to export to FBX, but still ran for about 20 mins and then crashed. The weird thing was, while it did max the RAM at times, when it finally crashed, it had been running for a couple minutes on ~80% RAM usage, 14% CPU usage, and 0% disk usage. That makes it seem like it’s not a resources issue - anyone have any other ideas what might be happening?
Edit: It also crashes while using nowhere near all of the available system resources when trying to export to Collada/.dae.
Final Edit: I couldn’t resolve the Blender issue itself, but found a workaround.
XNormal (thankfully!) allows you to use more than one high-poly object at a time when baking, so I just split my high-poly model into two pieces, and Blender was able to export both of those.