Trying to attach sockets to sockets (or SkeletalMesh to sockets)

Hi all,

Running into a bit of an issue; overall what I’m trying to do is assemble a modular gun from 9 different parts. The idea is that the receiver will be attached to the grip, and all other parts are attached to the receiver (other parts are barrel, scope, stock, magazine, and 3 accessories). I thought the best way to do this instead of manually punching in the offsets for where each part would go is to make bones (in the model) where they would snap/attach to and then add Sockets (in UE) to aid in that.

I’m having some weird issue where it for the most part works… but the main part (receiver) is right side up, while everything else is upside-down. I’m not sure why this happens, since I’m fairly sure all of my imported FBXs have the same orientation and I don’t have any transformation nodes. Below is the assembled gun before importing it into UE, the same gun during playtime (disfigured), a snippet of my Blueprint, and my FBS export options.

The highlighted is the skeleton for the receiver, and shows the points where all the other components should attach.

When gameplay starts and the gun is “assembled” using the below Blueprint, the receiver stays where it is while the other components mirror/rotate on the X axis. It assembles correctly, but upside-down.

Any ideas what I could be doing wrong here?

Addendum: I re-exported all of the models from Blender, just to make sure the settings were all the same. In addition, I also moved the objects so that the point I want to attach it by (the bone) is at the origin. Now it’s disfigured as well as flipped - are the components even attaching to the bones at all?

Well, turns out I accidentally switched the components where I was looking for bones; instead of trying to find the sockets in the receiver (which has 7 sockets) I was searching for them in the grip (which has 1 socket), and no error was thrown that no such sockets with the names I was looking for were found, so I didn’t even know an issue existed until I listed off the sockets each component was supposed to have and compared it with what was expected. It also seems I got the bone orientations wrong in-editor, and so am manually modifying the socket rotations to be correct.

I also just realized that this doesn’t explain why it (the grip) knows the socket positions despite not actually having the sockets.