BLI_bvhkdop functions were not made to work with zero-leaf trees. Perhaps a better solution would be to modify BLI_bvhkdop to work with zero leaf trees. But this solution of returning NULL was already used for bvhtrees of looptris.
BLI_bvhkdop functions were not made to work with zero-leaf trees. Perhaps a better solution would be to modify BLI_bvhkdop to work with zero leaf trees. But this solution of returning NULL was already used for bvhtrees of looptris.