Hi, I’m using regular UE 4.12.
When using the “Merge Actor” utility, I have a choice between “Pivot point at zero” and unchecked. Pivot point at zero is useful for merging actor and retaining its world location. However, when unchecking it, the resulting pivot point can be a bit unpredictable, especially when merging blueprints.
For instance, I’m creating “Cookie-Cutter” blueprints. The goal is to configure the blueprint to your liking, then as a final step, use the “Merge Actor” utility to combine all of the components into a single mesh for the purpose of reducing draw calls and improving performance.
Whenever I merge a blueprint, I want the resulting pivot point to be at 0,0,0 of the blueprint. So, instead of choosing one of the components as the pivot point, it should instead choose the origin of the blueprint as the resulting pivot point.
I can fool the editor into doing this by manually moving the blueprint to 0,0,0 in world space, then making sure “Pivot point at zero” is checked. However, these added steps can be a bit annoying.
Solution #1: So, I propose an option to go along with the “Pivot point at 0,0,0”… call it, “Temporarily move actor to origin before merging”. This would perform multiple steps. 1. Move actor to origin. 2. merge actor. 3. Move actor back to its original location.
Maybe this could be expanded to work with multiple actors selected. This would ensure the pivot point is never in an awkward, unpredictable Z location.
Solution #2: If that’s a bad idea, the perhaps this idea could be considered. When using the “Merge Actor” to merge a single blueprint, automatically assume the pivot point of the merged mesh should be the 0,0,0 (origin) of the blueprint. That would work well for single blueprints, but obviously not so well for multiple blueprints.
Solution #3: Here’s another idea: Include a checkbox that says, “Manually choose pivot point location”. When you check that, a “pivot handle” appears in the perspective and orthographic viewports. Just move this pivot point into location, then once it’s in place, then click “Merge Actors”. The location of the pivot becomes what the user selected. That could be the most ideal solution to this problem. 
Thanks,