Backpack guide: shapes, marked cells and weapon hands
Quick answer
Build around the weapon or character item you are actually using. Check three limits separately: whether the piece fits, whether its marked cells reach a useful target, and whether the equipped weapons exceed your available hands.
On this page
Make one working damage core
Place the main weapon where its support items can reach it. Rotate a held item with right-click on mouse controls, then inspect the highlighted cells before confirming. Adjacent icons are not enough when a selector points elsewhere or a modifier affects a different weapon type.
Upgrade without breaking the layout
Matching duplicates can be merged, but examine the result before committing in a tight grid. Removing one support can leave another weapon without the effect that made it usable. Compare the entire connected layout, not only the rarity color of the new item. Check free cells around your core when selecting backpack expansion.
Keep a purpose for each slot
Give each carried piece a job: damage, activation, recovery, movement or an immediate crafting requirement. Before a fight, check that you still have a usable weapon and an escape. In co-op, repeat that check on the seam between the two backpacks, because 1.0 selectors can affect the other player’s equipment.