Bf-pd is a library of pd objects for enabling real-time collaboration. This page describes each of the objects in bf-pd, their arguments, inlets and outlets.
bf-session
A bf-session represents a group of musicians (as represented by their bf-instruments) making music together. Within the bf-pd system a bf-session works “behind the scenes” to coordinate the data exchanged between bf-instruments.
To participate in a bf-session there must be at least one instance of bf-session instantiated somewhere. A bf-session has a name, e.g. “technoJam1”, and this session would be instantiated as [bf-session technoJam1].
There can be more than one bf-session object with the same name within the patches running in Pd. So you can add the same bf-session to each bf-instrument. (However if you instantiate two different bf-sessions within pd, the second one will not work.)
Arguments:
- The name of the session.
Outlets:
- Outlet 1 sends all the session messages which are used “behind the scenes” by the bf-pd objects.
bf-instrument
A bf-instrument represents a musical instrument within the bf-pd system. Each instrument joins a bf-session and can contain bf-params and bf-outputs. To create an instrument you should instantiate a bf-instrument with the name of your instrument, e.g. [bf-instrument myDrumMachine].
The audio output of your instrument should be connected to the first inlet of bf-instrument object. The interface has an activity monitor which shows a simple representation of the changing spectrum of the instrument’s sound, and the activity for each bf-instrument in the bf-session appears in the collaboration window. (Note: you must also send your audio to [dac~] in order to hear it!)
The collaboration window can be opened with the toggle in the bf-instrument object. If musicians enter or leave the session you may need to close and re-open the collaboration window.
Arguments:
- The name of the instrument.
Inlets:
- The audio output of your instrument should be sent here. (It must also be sent to [dac~].)
bf-param
A bf-param creates a user parameter within the bf-pd system. A bf-param can be controlled by the user of the bf-instrument it belongs to, and the bf-param will also be accessible to other instruments within the bf-session via the collaboration window, if the owner of the bf-instrument grants access.
A bf-param object has a user interface within the instrument patch itself, and it also creates a user interface in the collaboration window of each musician in the session.
A bf-param can be one of four types: * cont are numbers between 0.0 and 1.0. * midi are numbers between 0.0 and 127.0. * bool can take values of 0 or 1. * bang are bang messages which are used to trigger actions.
A bf-param can be a single instance of its type or it can be a multiple, which creates an array of values within a single bf-param object. For example, a bf-param “8 bool” creates an interface with 8 toggles, and might be used to represent 8 on/off values in a drum machine sequencer.
Arguments:
- The name of the instrument, e.g. “myDrumMachine”.
- The name of the parameter, e.g. “kickOnOff”
- The dimensionality of the parameter, e.g. “8”
- The type of the parameter, e.g. “bool”
So a bf-param with 8 drum machine note triggers would be: [bf-param myDrumMachine kickOnOff 8 bool]
and creates this object within your patch:

Inlets:
- Sets the value of the parameter. If the parameter is a multiple, then Inlet 1 sets the parameter at the index last received on Inlet 2.
- Sets the index of the parameter which will be changed by sending values to Inlet 1.
- An integer in Inlet 3 will send the value of the parameter at that index to Outlet 3.
(The first two inlets for bf-param operate similar to the first two inlets for [array set] in Pd.)
Outlets:
- The parameter value of the most recent change to the bf-param (whether that change came from the inlets, the UI, or via the collaboration window.)
- A list of the parameter value of the most recent change, and the index of the parameter that was changed.
- The parameter value for the index that was sent to Inlet 3.
bf-output
An bf-output can be used to send some musical data from your bf-instrument to another instrument in the same bf-session. A bf-output can have the same types and multiplicity as a bf-param.
Each bf-output in your bf-instrument will appear [TODO continue]
is a musical attribute that is produced by a module or instrument. They can have the same types as parameters. Outputs can be retrieved and watched by other instruments, and function as a means for both awareness and exchange.
Arguments:
- arg1
Inlets:
- blah
Outlets:
- blah
bf-watch
Bf-watch is used to get data from another bf-instrument into your bf-instrument.
Arguments:
- arg1
Inlets:
- blah
Outlets:
- blah
bf-ask
Description blah blah
Arguments:
- arg1
Inlets:
- blah
Outlets:
- blah