I try to make a sop output a terrain mesh also merge some points(with “unity_instance”, let's say tree points), after the merge, unwanted terrain points will have empty “unity_instance” and also 0 scale and 0 rotation. but when cook in unity, terrain points's scale&rotation apply to the first N tree points (N equals terrain point count)
After some dig, i noticed `GetInstanceTransformsOnPart` may have some parts calc issue, but i don't have time to review all GameDev code.
I guess i found some bug ? or i'm doing it wrong ?
