Hi Tim, apologies for bumping this old question, I believe I can elaborate upon OP’s request having thought of the same thing.
Blender can successfully export shape keys to UE4, this works well when you import the mesh as a skeletal mesh and enable the “import morph targets” option.
Now I understand Unreal also provides the option of morphing targets right within the material using the “StaticMeshMorphTargets” node. Based on the docs this node expects the data in a very specific format for which purpose you have provided a Max script to pack the data in the right form.
OP and I are wondering whether you can help provide a way for Blender users to also benefit from this node. Morphing within the material seems invaluable for applying morphs to static mesh emitters in Cascade.
I don’t know Blenders internals well enough to comment on how easy it is to provide a similar (python) plugin for Blender, do you have any thoughts on whether/how morph data from Blender can used with the the “StaticMeshMorphTargets” material node?