When Loopy Pro was initially released, only AUv3 effect parameters were mappable. All AUv3 can now have their parameters mapped.
There are a couple of main ways to MIDI Map Audio Unit Effect parameters:
You can also control AUv3 parameters with Loopy Pro's widgets: sliders, buttons and XY Pads.
To use the MIDI Learn system, turn on MIDI Learn. Tap on the AU's icon in the mixer (or tap on its icon from the main view if it is visible). A window pops up that lets you select learnable actions: Enable/Disable Effect, Open Effect Interface, Adjust Effect Parameter, Select Effect Preset. Choose Adjust Effect Preset and then pick the parameter to map and either send the MIDI event to learn or manually assign the event that you want to use.
To use the MIDI Control system, choose MIDI Control from Loopy's main menu and Add a New Binding. A binding is a mapping of a MIDI event (such as note, CC or program change) to actions. The Loopy Pro actions that control AUv3 parameters are:
This video demonstrates how to add a binding for an AUv3 Effect parameter using MIDI Control:
You can also use widgets to control the parameters of your AUv3s
Updated: June 2022 to include features added after the 1.0: release. These features include support for MIDI Fx AU, AUv3 instruments, and MIDI Learn of AU parameters.