OK, I’ve been thinking about the problem and here are my thoughts:
The pickup would of course be an Actor and I’d use a component, that has an exposed value weight.
To see what I’m picking up. A simple HUD (or rather just a simple cross) would suffice, to let me see the closest pickup actor under that cross (using a line-trace and some max range for the trace). And for simplicity, the player should just be able to pick up one actor a time.
For triggering the pressure plate, the pickup actor has to be in the trigger-volume, and is no longer carried by the player. The trigger volume takes all actors in its volume and adds up the weight to compare it with the desired weight value.
What do you think of it? Critics and comments welcome.