I have BuildParts a bit like rust. I load them all in as individual actors, so they are unrelated actors, and it seems I can’t “Group” them the way that the editor does.
I want my building to start with a random rotation after it’s loaded from file. I did this the unthinking way, and it was hilarious as you would expect, all objects rotated around their own pivot points.
I can use Get Actor Array Bounds to find the ‘centre’, but for all those buildparts to rotate around the centre I need to translate as well as rotate. Back in c++ I used to try and nut these thing out with matrix multiplications and trig. Is there an easier way in Unreal to treat a bunch of individual actors as a group?
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You can attach them to a central point, and rotate that.
Or, if you want to calculate it, you can take a vector from the central point, and use ‘rotate vector about axis’.
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Kind thanks! I found the API’s for attaching actors to actors and thanks again for the second option, that might be better for a building where the parts can be removed\destroyed to zero (where I would have to collapse away the root actor). Awesome answer!
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If you have a lot of attachments, things can get slow. If that happens, turn off the collision during the turn 
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This seems to be working for a static 30deg rotation. I can add RNG next. Very appreciative that you responded so quickly. Thankyou again. … and yes I’ll leave a comment in there to disable collisions if this ever gets slow. It’ll probably only be a load time routine.
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