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This is a patch from Aras Pranckevicius, D13927. See that patch for full details. On Windows, the many small fprintfs were taking up a large amount of time and significant speedup comes from using snprintf into chained buffers, and writing them all out later. On both Windows and Linux, parallelizing the processing by Object can also lead to a significant increase in speed. The 3.0 splash screen scene exports 8 times faster than the current C++ exporter on a Windows machine with 32 threads, and 5.8 times faster on a Linux machine with 48 threads. There is admittedly more memory usage for this, but it is still using 25 times less memory than the old python exporter on the 3.0 splash screen scene, so this seems an acceptable tradeoff. If use cases come up for exporting obj files that exceed the memory size of users, a flag could be added to not parallelize and write the buffers out every so often.