Patches and Subpatches in Pure Data


The following examples are based on patches and additional files, called abstractions. To make them work, all involved patches need to be located in the same direction (by cloning the complete repository). Arguments are passed to objects after the name, separated by a white space. The patch arguments-help.pd shows this by creating an arguments object:


Inside an abstraction, individual arguments can be accessed with the $ operator and their index. The loadbang is executed on the object's creation, thus printing both arguments on start. This is helpful for setting initial values in patches, as shown in arguments-help. Once created, it will print the arguments to the main Pd window:



Subpatches can be very helpful for creating cleaner patches without addtional abstractions and files. To create a subpatch, use the object pd with an optional string argument for naming the subpatch. They can be used like abstractions but do not require an additional file.


When toggling Graph-on-Parent in an object's properties, it can expose GUI elements to its parent patch. This is a good way of cleaning your patch and showing only what is needed in a performance situation. It works for both abstractions and subpatches. The example patches.pd makes use of this to create a filter subpatch with controls. The left hand audio input of the suppatch is a fixed frequency sawtooth. The right hand control input sets the Q of the filter.


On the inside, the moog~ object is used. It is not part of PD vanilla and can be installed with the flatspace ggee extensions from Deken. The red rectangle marks the area visual in the parent patch. All GUI components inside this area will be visible:


Inlets and Outlets

The patch has two inlets - one in audio rate (inlet~) and one in control rate - and two outlets, also with audio rate (outlet~) and control rate. For inlets and outlets, their horizontal order determines their order in the object when patched from the parent. Changing them can mess up the complete patching.