Hi Stefan - the VFX assets will load just fine in the UE4 Modeler, but they may have intersecting triangles in the leaf meshes which wreak havoc with our lightmap UV generation. The UE4 Modeler will complain upon loading if is the case. The assets in the UE4 tree library have been carefully adjusted so won’t happen, plus we’ve gone ahead and tuned the lightmap UVs for every variation and resolution. To us, was one of the biggest features we brought to the table. Ever tried to generate efficient unique UVs for a generic 3D tree mesh? Ug. We were trying to end a nightmare a lot of people were complaining about.
Plus, the VFX assets are more expensive because they’ll often have 2-3M triangle models.
Hope helps!