BP with blocking collision within a parent actor BP causing weird physics

Hi All,

I’ve recently come across an interesting issue with physics and child BPs which is likely due to a fundamental misunderstanding of BPs or collisions. Regardless, the issue that I’m having is that I have a ship BP, within the ship BP there is another BP for the cannon, the wheel, anchor, just to name a few. With ANY of these blueprints having ANY world dynamic blocking collision enabled on any subcomponent physics seems to not act appropriately.

If I have all of the blocking collisions set to no collision on the child BPs (cannon, wheel, etc) and then “Add Force” to the ship actor it acts as expected, moving in the direction I want. However, when any of these other blocking collisions are enabled on the child BPs then the force added to the ship actor seems to interact with something else. See the pictures and video below for more info.

My question is should I be architecting this differently? The cannon, wheel, and anchor all seem to be prime candidates for BPs since I want logic contained to hose actors (aiming & firing the cannon, rotating the wheel, dropping the anchor). Also, I need collision on these items so actors can’t walk directly through items. Should I be putting this logic in another area or are there other approaches to dealing with this issue? I’ve attempted to scour the internet and that has failed me so any insight would be lovely! Please let me know if there’s anything else I can add to the post that would help. Thank you in advance.

Video without any blocking collisions enabled (yes, I know it’s a floating boat but it’s to illustrate. Also sorry, since I’m a new user I can’t upload attachments if there’s a better way to share these snippets please let me know)

Video with 4 total blocking collisions (two small box collisions on the cannons on each side of the ship, picture of cannons included)