The "functional" crossbow from the video game "The Witcher 3". The term "functional" refers to the fact that it can fire foam arrows.

Required materials:
A small spring that is about 15 mm long and 8 mm wide.
An elastic rope about 30 centimeters long and with a diameter of about 2 to 4 millimeters.
Two 35-millimeter Chicago screws.
A thin rope or hemp rope.
Two-component epoxy resin adhesive or other high-strength adhesives.

Assembly steps:
Please print the model files in the attachments separately. When printing, you can perform appropriate slicing on the crossbow body according to your actual needs. It is recommended to first complete the assembly of the crossbow body, and then proceed to install the internal mechanisms.

Use high-strength adhesives such as two-component epoxy resin glue to firmly bond the "bow" part of the crossbow - that is, the left and right bows - to the crossbow body. Unlike traditional real crossbows, this crossbow uses elastic ropes to provide pulling force, rather than relying on the plastic bow body itself. Therefore, the bow body part must remain rigid and not be easily bent.

We strongly recommend that you carefully study the mechanical structure of the crossbow and gain a deep understanding of the way the trigger fits into the crossbow body. If you want to make more precise adjustments, you might as well first print a small-sized "fit test" model that only includes the trigger area, so as to better grasp the overall assembly details.

When assembling the trigger mechanism:
Stick the spring directly on the back of the trigger, in a position directly opposite the "conical" structure protruding from the top.

Place the circular rotating shaft at the bottom of the crossbow body, with the duckbill-shaped end facing up and pointing towards the top of the crossbow body; at the same time, ensure that the groove for fixing the rope is facing forward. Then, insert a Chicago screw through the upper hole.

Insert the trigger into the hole at the bottom of the crossbow body, with the spring side facing the back of the crossbow body. Then, screw the second Chicago screw into the hole from below. At this point, the trigger mechanism has been largely assembled and can function normally.

Tip: To prevent the trigger from shaking sideways during use, it is recommended to install one or two accompanying shims between the trigger and the crossbow body to ensure stability.

Slide the "string puller" into the two holes on the back side of the handle. This component can pull the bowstring back to the top of the trigger rotation axis after each shot, allowing for automatic reset and keeping the crossbow in a "ready to fire" state at all times.

It is wrapped around the left and right sides of the bow with a fine rope or hemp rope, adding a touch of medieval simplicity to the entire work.

Pass the elastic cord through the two ends of the bow arm, so that it is slightly loose when not tensioned, and very tight when fully tensioned. It is recommended that you try several different tension settings to find the most ideal balance of tension. In addition, it is necessary to remove the bow string in time when not in use, which not only prolongs the service life of the elastic cord, but also effectively prevents the performance degradation caused by long-term stress.

It's done! Load the foam arrows and enjoy the fun of shooting!