Drawing With Voltages

It's a Christmas tree.

There is a reason why most–if not all–video synthesis images are either abstract compositions or processed external imagery. Direct figurative drawing using only voltages is tricky. You need to really know the ins and outs of each module and how they can be used together. It also helps to have an image in mind that is possible given the constraints of the system.

Constraints such as: positioning the image elements on the canvas. It seems like such a fundamental thing–being able to place a circle here or a square there–especially if you are coming from years of being able to put pencil to paper wherever you want. Even if you're coming from years of Photoshop, not being able to nudge something to the left or right can be really brain-breaking. Another constraint you often run into is element mixing and colorization. If you have limited compositing options, you need to simplify your design to something that works with only a few layers and a limited palette.

Rockin' Around the Christmas Tree

For Christmas this year, I decided to try my hand at a Christmas tree. It seemed simple enough: I can use ramps and logic to get a triangle, a modulated oscillator can apply some lights and garland, and with a touch of noise, we can make it snow. Here's the result:

Patch Breakdown

Here's the finished patch diagram. I'll walk through each element in turn:

The Tree

The tree itself consists of a horizontal "tube" ramp and a left-right vertical gradient ramp mixed in an Arch. The Intersection output of Arch will display only the gradient triangle shape. Perfect.

Okay, here's my one little cheat: the tree is sideways. Whenever I'm composing for my daily patches, I'm working in a vertical 9:16 aspect ratio. In order to make that work, I take the 4:3 recorded output, trim it down to 16:9 and then rotate the video as part of the last step of export. I've gotten so used to this workflow that my brain can interpret a hot-off-the-modular patch and know how it is going to work when it's rotated 90°.

If you want to avoid that last rotation step, you can flip the ramp inputs and use a vertical "tube" ramp and a top-bottom vertical gradient ramp instead.

The Sky

This one you get for free. After constructing the tree, you take the Minimum output from the Arch to get a nice night time winter sky.

The Lights & Garland

For this, you need to take a Video Waveform Generator (or other video oscillator) synced and running as stable vertical lines. I'm modulating this oscillator with a Sine LFO to get the characteristic swag shape and also modulating it with a faster Triangle LFO to get some animation along that swooping shape. The Triangle Output of the VWG is then fed into a Cadet VIII Hard Keyer. I tweaked the keyer Threshold knob so that the oscillator lines were thinner and I also modulated that keyer with the Clip output of the Arch. This last modulation shapes the wavy dancing lines to conform (eh, roughly) to the shape of the tree triangle.

The Topper

This element was the one that gave me the most trouble. I knew I wanted something to sit atop the tree, but like I said, positioning it can be a losing battle. Let alone be something star-like. And yellow.

One quirk of mixing those two ramps in an Arch is that the Maximum output generates a rectangle at the point of the triangle. Useful. Now, to turn it from a rectangle into something more appropriate, I fed it into another Cadet VIII Hard Keyer and modulated that keyer with the Triangle Output of another Video Waveform Generator (or another video oscillator). This VWG, like the other, is synced and running as stable vertical lines. Manually adjusting the Frequency knob on the VWG allowed me to tune in a diamond shape for the topper.

The Snow

One of my favorite tricks with a Staircase is no-input self-patching feedback to generate video noise. Take the ÷2 Output and plug it into the Source. Take the ÷4 Output and plug it into the Frequency VC Input. Turn the Frequency and Frequency VC Input knobs and you will have an adjustable amount of video noise on the ÷1 Output. I went for something a little sparse here. Not quite blizzard conditions.

Putting it All Together

All of the compositing is handled by a Color Chords. The layering here matters, so it helps to work from background to foreground. For the sky layer, I just plugged it into the Blue Input on Layer 4. Layer 3 is the tree, which I tuned to a very Christmas-y green. The snow goes into Layer 2, which I tuned to white. The lights & garland go into Layer 1, tuned to a yellow/white color.

For the topper, I used a quirk of the input normalling on Layer 4: since the sky is using the Blue Input, anything plugged into the Red Input will be normalled to both the red and green channels, creating a yellow image on the output. Perfect.

Conclusion

All told, not bad for 10 minutes of patching, but I think you can see that it requires a bit of an abstracted approach. You need to think about individual elements and how you're planning on combining them 5 or 6 steps down the line. It helps to be efficient with outputs you already have: don't create an elaborate sub-patch if you can pull another element from the Arch and work it in somewhere. Use "hidden" features like self-patched feedback and input normalling to your benefit. Keyers are indispensable as element shapers.

The second I finished this patch up, I thought, "Oh, I should have done x, y, z instead." There's always room for improvement in something like this and it's a fun brain teaser to boot. I'm thinking that I'll take another run at this one next December and see if I can't come up with another detail to work into the composition.