One of my main responsibilities on Avatar was leading the team that made props for Virtual Production. WETA Workshop would make a Hero Prop, then WETA Digital would 3D scan it to make the final CG Version, then the Hero Prop would be sent to Jim to approve. Once approved, my team would make a version for Virtual Production.
All Na’vi carried knives and each of the principal characters had unique designs. Jake’s knife was the only knife to be used by a human so there was a giant prop built.
Arrows were also unique to the character using them since their length was determined by both the size of the bow and the arm that drew the bow string. Neytiri’s arrow was disproportionately longer and featured a much larger arrowhead so that there was enough room for a wood sprite to land on the end.