Acoustic Hole Connection

The 'hole connection can be created using the following Lisp syntax:

The 'hole connection takes four arguments:

• access_ref: any access.
• radius_ctl: radius of hole (in meters).
• noise_ctl: hole noise coefficient.
• weight: (optional) controller weighing the interaction.

The weight controller is optional. If not provided, it defaults to 1.

This interaction internally creates a small closed-open tube and adheres it to the access you provide. Since the hole radius is given by a controller, the hole can be opened and closed dynamically. The noise coefficient is expected to be between 0 and 1; when it is high, then opening and closing the hole produces some air turbulence in the tube (although this has not been tested much and seems to have very little effect...).

Here is an example of how to open and close a hole over 2 seconds:

Note also that If the hole is too large, the system may become unstable and will not produce sound.

This connection has been deprecated, but nonetheless still retained in the Modalys environment. You should now create a Modalys object (such as a very small closed-open tube), typically with few modes, to act as a hole and connect it with an 'adhere connection to your object acting as a tube. (Which is basically what this connection does, anyway.) The hole will be made more or less active (more or less open) by varying the weight controller of that adhere connection. If you really want to use the hole connection, please note that the radius is made internally to .01 m by default, so please adapt your radius messages accordingly.

A very small closed-open tube like this can be adhered to another tube as an alternative to making a tone hole on a wind instrument:

This tone hole is adhered to a resonating air column (i.e. another tube serving as the instrument itself) at the closed end of the tube. Opening and closing the tone hole is achieved by modifying the interaction weight of the adhere connection itself. (A weight of 1 means the hole will be open, a weight of 0 means it will be closed.