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My Learning Journey 03 - Okay, CHOPs make my head hurt a little

I have now finally reached the CHOP section in the youtube video "Absolute Beginner TouchDesigner | From Zero to Hero with Examples and Assigments" by Acrylicode and I see this is the part where Touchdesigner separates the men(artists) from the boys(programmers). In order to do operations with simple interpolations between two points, something that would take about a line or two of code in a game engine, I have to create a frightening network of nodes and connect them to specific values in other CHOPs and TOPs. While this does allow for a large amount of customization and fun visuals to emerge, this creates an equal number of ways for things to go wrong. My brainy no likey!

I'm going to write down some CHOPs that were used in group because if I don't memorize how they all interconnect as a system, this is going to be hell.

  • LFO, Math, and Null - The low frequency oscillator (LFO) node helps create the basis of a steady rhythm with parameters I can control. But it always only oscilates between zero and integers of 1. By combining it with the "Math" node, I can extend the range (I have to go to the range tab) to my needs. This is similar to writing a lerp/interpolate function in programming. The instructor then says I should close out the network with a "Null" node. Now, by applying this network to specific parameters within TOP nodes, I can make them move over time, for example, making a circle oscillate back and forth on the canvas.

There is a more precise way to create patterns as well. If I want to do something more complex than a simple oscillation, this is the network I would most likely use:

  • Beat, Pattern and Lookup - Beat will move from 0 to 1 and then snap again back to 0. If I use a lookup node with any pattern node using a beat as a reference, I can customize a variety of different movements. lookup will map values along the pattern and output them into values I can use over time. I can use unusual noise patterns as well as more common sine waves and so on. I should also close this out using a null node to keep things organized.

There were just a couple more nodes that the instructor gave me to cover the basics, some additional ways to modify CHOP values:

  • Lag - Offsets the time of a beat or LFO by a set value. by stacking several lags I saw I can create these beautiful wave patterns (as seen in the attached photo)
  • Filter - Sharpens or smooths out a pattern node. I haven't gotten to play around with this yet but I'm sure its useful.

I did manage to finish the first two CHOP assignments by the instructor without a scratch, so maybe I'm starting to get the hang of it? We'll see.