There’s a chase scene in some version of The Three Musketeers where one of the Musketeers cuts the rope of the chandelier above him to simultaneously trap the pursuing guards under the fixture, and hoist himself onto the second floor with the rope. For fun, we’ll try to re-create the mechanics of the falling chandelier in VR with our developments in rope-cutting and grabbing.

We begin by placing the curtain pulley system into a new scene, and re-attaching it to a chandelier model hung above the player.

Our goal is to allow the player to use a scissor-gesture to cut the rope that their other hand would be grabbing, to launch them towards the chandelier. To do so, we use hand tracking to manipulate the character’s controller with gravity turned off, so that the player’s position is dependent on the position of the rope. 

Our first attempt resulting in a bug that caused the player, rope, and chandelier to fall towards the ground. (↓)

It is difficult to see what is happening with the chandelier, so we move both the pulley and the rope up to increase the length of the rope, and the strength of the pull. The chandelier is also adjusted to be in-frame by moving the pulley system farther back. (↓)

We’re able to make the player follow the rope’s position from side to side, but it becomes more difficult for the player to move upwards. The player moves up a bit initially, then suddenly stops. The issue is the scene’s gravity which is promptly tweaked. (↓)

So here we figured out how to get the player’s movement to follow the position of their hand grab position on the rope. However, the up-and-down movement of the hand ignores the rope’s mechanics, and the player is stuck in a perpetual upwards motion until the rope is let go. (↓)

The issue is the result of the player’s lack of weight, which means there was nothing to counterbalance the chandelier. The issue? In order to move upwards while grabbing the rope, we had turned off gravity entirely. The XR rig also uses a character controller rather than rigidbodies, which means there was no easy fix for this issue. 

Our biggest takeaway from these developments is that we must do more work on rope-grabbing. Instead of using hand-tracking to grab rope, we need to use Auto Hand to integrate physical hand integrations, which will also resolve the gaping issue between the player’s hand and the rope.