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Our next Folk open house will be in the evening on Wednesday, September 30, at our studio in Williamsburg, Brooklyn.

• editor: Only target the smallest program the editor points at
  • Fixes this issue where an editor pointing at two programs at once results in two unusable/wire-crossed editors:
    • (especially annoying when on a viewport, since the editor would always point at both the viewport and any program inside the viewport)
• Fixed how bare claims totally broke Folk by triggering everything
  • (for example, if you just put Claim on a line on its own in a program, it would break the whole system)
• prelude: Fix function replacement when a new in-scope ^function should stomp the old one
  • Should finally fix the random space changer failures which would fill up the log! (was happening when space changer initialized to null changer and then filled later, but original changer function was not actually replaced)
• /program/<whatever> Web endpoint: Show the edited version of the program if it's been edited
• Made destructor inheritance dedupe on each set add, which fixes destructor blowup (and therefore out-of-memory; you can have millions of destructors, only 4-5 of which are unique) in cycles of reused/reinherited statements (which seem more common now? not sure why? I think it was maybe from editor pointing at itself during rapid movement, causing an inheritance cycle?)

Made a few major fixes to Atomically to fix blinking and stuckness issues with it.

1. Add correct dbInflightDecr on the exit path where provisional statement is immediately thrown away (to make sure the inflight doesn't stick forever and keep the new version from converging)
   • Should fix “(edited)” titles sticking around randomly / after program revert.
2. Support multiple inheritance so a Match or Statement can be part of multiple AtomicallyVersions at once (from different keys)
3. One-way hasConverged (latch convergence)
4. Timeout by parent removal

Also comes with a new version of the animation program that should blink much less and be more reliably timed.

Omar: As long as I can remember, the editor has been the slowest thing in the system, where you point an editor at a program and the whole system slows down noticeably. It's especially bad on programs that have a whole page of code (that's like 2,000 glyphs).

I benchmarked it this month and found that a 2,000-glyph editor slows the system down to 8fps (and this is on the global GPU thread, so it slows everything else down too).

Simple fixes: cache the C encoding of all Tcl draw calls and turn off the Vulkan validation layers. That immediately brings us to 40-50fps. Much more usable.

Next, I want to do more editing and terminal I/O in the system. I think we can also push draw call batching further and maybe then bring back the validation layer.

Embedding-based tracking has a number of advantages compared to SAM2 tracking or raw contours (last month).

It lets you do re-identification, where you take the object out of frame and bring it back seconds or minutes later. How do you maintain tracking without the visual continuity between frames? Embeddings use the inherent appearance of the object, which is also easy to serialize, instead of visual continuity like the SAM2 predictor.

Embeddings are fast – you can compute an embedding of a pose or viewport in like 10ms – and are fast on almost any hardware, even my low-end home Intel N95 GPU (which can run DINOv2 in 100 or 200ms but takes 2 seconds to run SAM2).

They let you get these really nice intepretable heatmaps of what the most 'cup-like' or 'army-toy-like' 'earbuds-case-like' (or whatever you want to find) regions of the viewport are.

Here, the top heatmap shows bright army-toy-like regions, and the bottom heatmap shows bright cup-like regions (notice how they follow when I move the objects):

More heatmaps:

Here's DINOv2 with NCC but no rotation tracking, which is remarkably fast and accurate for a radially symmetric object like this cup:

You can get pretty impressive fine centers:

Harder to deal with asymmetrical objects. Need to record several poses with known rotations, find the best cross-correlation, use that to give angle.

Omar: As part of the RTBW project, Brian, John Williams, and I have been mounting and bringing up the CNC system. Mounted steel strut to ceiling, hung 2 cameras and a projector (cantilevered on wood block).

It took a while to figure out how to mount the projector, because it projects in a triangle upward from its bottom plate, and our strut wasn't really in the right spot to mount it widescreen. We tried complicated rigs like this to move the projector vertically away from the strut:

but felt uncomfortable mounting them. Eventually just went with turning it 90 degrees and doing the cantilever for now.

We also remounted folk-convivial from the ceiling:

Weirdly, both of our Intel N95-based mini PCs seemed to have fried SSDs when I tried them. I ran into this issue on my home system after about a year, too. Replaced the SSD and put a 3D-printed spacer in to make the new SSD the right length:

Verified that the CNC machine itself works to cut some wood for the mount:

For the RTBW project, I've been mounting a varifocal-lens camera 15-20ft away (alongside the 4K projector) to try to target a 6ft x 10ft CNC bed.

I can configure the lens to the right field of view, but can't mechanically get it to the right place to focus it while keeping it all attached. Need to buy a ring adapter to push the C-mount lens further out, I think? Haven't fully figured out.

Mason: Omar and I (among others) have been continuing to discuss what an [Expect] command would look like. The idea is you could use [Expect] like:

Expect Omar likes color /omarColor/
Expect Mason likes color /masonColor/
if {$omarColor eq $masonColor} {
  Wish $this is labelled "Mason and Omar like the same color"
} else {
  Wish $this is labelled "Mason and Omar like different colors"
}

This doesn't look too different than the current [Expect!] command, but it's more powerful, since it will rewind any effects it caused, then rerun the code. For example, if I changed my favorite color to blue, but Omar's stayed red, it would undo the “same color” wish, then run again, wishing the “different colors” branch the second time through. This would make a number of things easier to work with, but the biggest benefit in my mind is that you can have [Expect] inside a function. This means something like point conversion would become

proc pointProject {fromPoint toSpace} {
  Expect tag [lindex $fromPoint 1] has quad /fromQuad/
  Expect tag $toSpace has quad /toQuad/
  # Conversion code here
  return $converted
}
set projected [pointProject [point 0.1 0.1] 123]

Now “projected” would update any time either quad changed. It becomes almost like Excel, where I can just say “A1+B2”, and it'll automatically update as dependencies change. Except now it's just normal code! There's a number of finicky details though: [Expect] introduces some nasty race conditions, because it can be triggered at any point a new value comes in. This is particularily difficult with things like files:

Expect the filename is /filename/
set fd [open $filename]
set contents [read $fd]
# What if Expect gets a new value right here, and rolls back? [close] will
# never be called, so we'll leak the fd.
close $fd

So, you might say, just close every resource that's still open, right? Well, that opens up a different can of worms (though this is more contrived):

Expect the filename is /filename/
set fd [open $filename]
Hold! the fd is $fd
# What if Expect gets a new value here? It will roll back, closing fd in
# the process, even though fd stays visible.

I think in general I'd prefer the second option, because it means that things are closed instead of leaked.

Another (more cursed) idea I had that stems from rewinding is propagating errors by rewinding to the problematic statement, and having the error raised there. For example:

Wish to draw a circle onto 123 with cnter [list 0.2 0.2] ;# Has cnter typo
Wish $this is labelled "here"
# Code has now run both wishes

Later…

When /someone/ wishes to draw a circle onto /p/ with /...options/ {
  # Error is raised here, since no center was provided
}

Now, the error would propagate up to the original wisher, and the code in that block would rewind back to the problematic statement. That means the “labelled” wish would undo itself, the error would occur at the circle wish, and a stack trace would contain each intermediate statement that led to the error.

Paul: I am in the process of building out a Folk music toolkit, and one of the core components needed for this system is the ability to send OSC messages from my Folk machine to arbitrary OSC servers to control synthesizers. I managed to implement simple OSC send functionality which allows Folk users to send OSC messages using the native Folk `Notify:` syntax. A Folk environment first registers the address of the OSC server using `Claim the NetAddr is <ip>:<port>` then once an endpoint is registered Folk programs can send OSC messages using the syntax `Notify: OSC at /path/ with args /values/`.

Next I will add support for OSC bundles, which will allow us to write proper tidalcycles-esque pattern languages native in Folk!

: Andrés or Daniel

: Andrés

Tracey Le has been bringing in smaller groups from the current Recurse Center batches who want to do some programming in the 87R systems (and maybe bring knowledge and practices back to the RC system).

Had a pretty big open house (we've been having big open houses for the last few months). Tracey brought a bunch of people from Recurse Center; Alan Laidlaw stopped in for the first time in a while; Paul came up from Philadelphia.

Nice to have: New fast editor + lack of multi-editor bug when pointed at multiple things.

Ran into bug with editor still crashing/multi-appearing a couple of times:

• Our next Folk open house will be on Wednesday, September 30, at our studio in Williamsburg.
• Omar: Ship RFID tracker
• Omar: Build automatic folk-cnc driver and preview application
• Omar: Calibrate RTBW CNC system
• Omar: More work to make editor usable on table
• Omar: Filter DINOv2+NCC+rotation tracker to be more stable; integrate with DrawTalking strokes
• Andrés:

• http://batteries.parametrek.com/index.html?mah=1514,_&voltage=7.4V,8.4V
• https://learn.adafruit.com/li-ion-and-lipoly-batteries/rc-type-batteries
• https://www.billbuxton.com/tapeDrawing.htm
• https://www.mathartfun.com/DiceLabDice.html
• https://memoryboard.com/
• https://freckle.tech/
• https://chompshop.com/
• https://engineering.stackexchange.com/questions/25999/stopping-reducing-wobbliness-in-threaded-rod
• https://lightbulbcomputer.com/