When I was looking at this stuff it did seem like the different transform styles had some spotty implementations - for example SpeedTree-related code would do something a little different from other code, and certain combinations of transform styles and setups didn’t seem well-supported. In fact I think I changed a little code here and there but I can’t remember how exactly - I either copied a couple lines out of speed tree implementation or pasted a few lines into it from other places that were better behaved.
In particular, my memory is fading, but in unreal code there were a couple different defines that did similar things around instancing. Like #INSTANCED and #PARTICLE_INSTANCED (that’s not what it was, but it was something like that), and some code paths only handled one or the other.
It “appears” EPIC has re-written the Imposter Baker Plugin in 5.5 and improved things a lot along with written some Documentation about it though I haven’t had a chance yet to use it myself.
Installed UE 5.5, but couldn’t get ImpostorBaker to work.
Some blueprint functions are not working. Found that enabling GeometryScript plugin for my project fixes the errors insideBP_Generate_ImpostorSprites.
But even still the function CreateMaterialInstanceFromBaseMaterial is missing inside EUW_Impostor_Editor and I have no clue in which Plugin it is found. Probably some kind of non-engine plugin, cause I couldn’t find it in C++.