OBJ files exported from other programs can contain a large number of segments, which affect animation performance and can cause UE to crash.
These segments can be created as a result of exporting thick fabrics with many edges, stitches, etc.
We recommend to keep the number of such segments below 120.
In Maya, you can use Merge function with 0.01 Threshold to lower down the number of the segments. You may want to experiment with the Threshold value to bring the number of the segments below 120.
For example, this jacket was exported from Marvelous designer.
After we imported it as-is into UE with uDraper plugin, we had very low FPS during animations.
If we separate the jacket mesh in Maya, we can see that it has almost 3,000 segments.
If we apply Merge command to the jacket mesh with 0.01 threshold , the number of segments drops below 120.
After exporting this merged mesh from Maya in OBJ format and importing into UE, performance increased dramatically during the animation.
Similar approach also helps to prevent UE crash during movie rendering.