TouchDesigner MIDI Out: A Simple Guide

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TouchDesigner MIDI Out: A Simple Guide

Hey everyone! Ever wanted to control external hardware or software using TouchDesigner? Well, one of the coolest ways to do that is through MIDI (Musical Instrument Digital Interface). This guide will walk you through the basics of setting up MIDI out in TouchDesigner, so you can start sending those sweet, sweet signals to your synths, lighting rigs, or whatever else tickles your fancy. Let's dive in!

Understanding MIDI and TouchDesigner

Before we get our hands dirty, let's quickly cover what MIDI is and how TouchDesigner plays along. MIDI is essentially a language that electronic musical instruments and computers use to communicate. It doesn't transmit audio; instead, it sends messages like note on/off, control changes (knob movements), and program changes. Think of it as sending instructions rather than the actual sound.

TouchDesigner, being the versatile visual programming environment it is, has excellent MIDI support. You can both receive (MIDI In) and send (MIDI Out) MIDI messages, making it perfect for creating interactive installations, controlling audio-visual performances, and even building custom MIDI controllers.

Why Use MIDI Out in TouchDesigner?

  • Control External Synthesizers: Imagine tweaking the knobs on your favorite synth directly from a TouchDesigner interface. MIDI out makes this a reality!
  • Automated Lighting Control: Send MIDI messages to DMX controllers to create synchronized light shows.
  • Interactive Installations: Trigger events in other software or hardware based on user input in TouchDesigner.
  • Custom MIDI Controllers: Design your own unique MIDI controller using TouchDesigner's UI tools and send MIDI messages to control other devices.

Setting Up MIDI Out in TouchDesigner

Alright, let's get to the fun part! Here’s a step-by-step guide on how to set up MIDI Out in TouchDesigner:

1. Adding the MIDI Out CHOP

First things first, you need to add a MIDI Out CHOP to your TouchDesigner network. The CHOP family of operators in TouchDesigner deals with channel data – think of it as streams of numbers. The MIDI Out CHOP takes these numbers and converts them into MIDI messages.

  • Create a CHOP network: In your TouchDesigner project, navigate to where you want to place your MIDI output. This could be in a new container or within an existing network.
  • Add the MIDI Out CHOP: Press Tab to open the operator menu, type "midi out", and select the MIDI Out CHOP. This will add the operator to your network.

2. Configuring the MIDI Out CHOP

Now that you have the MIDI Out CHOP, you need to configure it to send MIDI messages to the correct device. Double-click the MIDI Out CHOP to open its parameters.

  • Device: This is the most important parameter. It specifies which MIDI device you want to send messages to. Click the dropdown menu and select your desired device. If your device isn't listed, make sure it's properly connected to your computer and that the drivers are installed correctly. Sometimes, restarting TouchDesigner can help it recognize new devices.
  • Channel: This specifies the MIDI channel you want to send messages on. MIDI channels are like separate communication lines within the MIDI protocol. Usually, you'll want to stick to channel 1 unless you have a specific reason to use a different channel.
  • Note On Velocity: This parameter sets the default velocity for note-on messages. Velocity determines how loud or strong a note is played. A value of 127 is the maximum velocity, while 0 is the minimum.
  • Control Map: This is where the magic happens! The Control Map parameter lets you map incoming CHOP channels to specific MIDI control change (CC) messages. We'll dive into this in more detail later.

3. Creating CHOP Data to Send

The MIDI Out CHOP needs CHOP data as input to generate MIDI messages. This data can come from various sources, such as LFOs, Math CHOPs, or even external sensors. For example, you can use a slider to control a MIDI CC value. Here's a simple example using a Constant CHOP and a Math CHOP:

  • Add a Constant CHOP: Create a Constant CHOP and name it something descriptive, like "slider_value".
  • Set the Constant value: In the Constant CHOP's parameters, set the value to a range you want to control. For example, if you want to control a MIDI CC value from 0 to 127, set the Constant value to a range between 0 and 1.
  • Add a Math CHOP: Create a Math CHOP and connect the Constant CHOP to its input. The Math CHOP allows you to remap the input range to a different output range.
  • Remap the range: In the Math CHOP's parameters, set the "To Range" to 0 and 127. This will remap the Constant CHOP's output to the full MIDI CC range.

4. Mapping CHOP Channels to MIDI CCs

Now that you have CHOP data, you need to map it to specific MIDI Control Change (CC) numbers. This is done using the Control Map parameter in the MIDI Out CHOP.

  • Open the Control Map: In the MIDI Out CHOP's parameters, click the "+" button next to the Control Map parameter. This will open a table where you can map CHOP channels to MIDI CC numbers.
  • Add a mapping: In the first column (CHOP), enter the name of the CHOP channel you want to map. For example, if your Math CHOP is outputting a channel named "chan1", enter "chan1" in this column.
  • Set the CC number: In the second column (CC), enter the MIDI CC number you want to control. MIDI CC numbers range from 0 to 127. Refer to the documentation of the device you're controlling to find the correct CC number for the parameter you want to control.

5. Sending Note On/Off Messages

Besides Control Change messages, you can also send Note On/Off messages to trigger notes on a synthesizer or other MIDI device. To do this, you'll need to use a different approach:

  • Use a Trigger CHOP: The Trigger CHOP is perfect for generating short pulses when an input value changes. You can use this to trigger Note On and Note Off messages.
  • Map to Note and Velocity: In the MIDI Out CHOP's parameters, you can specify which CHOP channels correspond to the Note and Velocity values. When the Trigger CHOP outputs a pulse, the MIDI Out CHOP will send a Note On message with the specified note and velocity. When the Trigger CHOP's output returns to zero, the MIDI Out CHOP will send a Note Off message.

Example: Controlling a Synthesizer Filter Cutoff

Let's walk through a complete example of controlling a synthesizer's filter cutoff using TouchDesigner MIDI Out.

1. Create the Network

  • Create a Constant CHOP named "filter_cutoff". Set its value to 0.5.
  • Create a Math CHOP and connect the "filter_cutoff" CHOP to its input. Set the "To Range" to 0 and 127.
  • Create a MIDI Out CHOP and connect the Math CHOP to its input.

2. Configure the MIDI Out CHOP

  • In the MIDI Out CHOP's parameters, select your synthesizer as the Device.
  • In the Control Map, add a new mapping. Set the CHOP to "chan1" (the output channel of the Math CHOP) and the CC to the MIDI CC number that controls the filter cutoff on your synthesizer. (Consult your synthesizer's manual for this number. It is often CC#74).

3. Test the Setup

Now, when you change the value of the "filter_cutoff" Constant CHOP, you should hear the filter cutoff on your synthesizer change in real-time. Congratulations, you are sending MIDI from TouchDesigner!

Troubleshooting Common Issues

Setting up MIDI can sometimes be a bit tricky. Here are some common issues and how to solve them:

  • Device Not Listed: If your MIDI device isn't listed in the MIDI Out CHOP's Device menu, make sure it's properly connected to your computer and that the drivers are installed correctly. Try restarting TouchDesigner and your computer.
  • No MIDI Signal: Double-check that you've correctly mapped the CHOP channels to the MIDI CC numbers. Use a MIDI monitor (a software that displays incoming MIDI messages) to verify that TouchDesigner is sending the correct messages.
  • Incorrect Control Range: Make sure that the range of your CHOP data matches the expected range of the MIDI CC parameter you're controlling. For example, if a MIDI CC parameter expects values from 0 to 127, make sure your CHOP data is also in that range.

Advanced MIDI Techniques

Once you've mastered the basics of MIDI Out in TouchDesigner, you can explore more advanced techniques:

MIDI Feedback

You can use MIDI In to receive MIDI messages from your external devices and use them to control parameters in TouchDesigner. This is great for creating interactive systems where the hardware and software respond to each other.

Sysex Messages

Sysex (System Exclusive) messages are special MIDI messages that are specific to a particular device. You can use Sysex messages to control parameters that aren't accessible through standard MIDI CC messages.

Scripting MIDI

You can use Python scripting in TouchDesigner to create more complex MIDI interactions. For example, you could write a script to automatically generate MIDI sequences or to map multiple CHOP channels to a single MIDI CC number.

Conclusion

Alright, guys! You've now got a solid understanding of how to set up MIDI Out in TouchDesigner. Experiment with different CHOPs, MIDI devices, and control mappings to unleash your creative potential. Remember to consult the TouchDesigner documentation and the documentation for your MIDI devices for more in-depth information. Happy patching!