desktop: hangs on a difference of a union of a union…?

I have a design where I struck an issue with just adding to a negative volume by using union. The boolean ops are nested quite a lot, but I haven’t struck issues with that previously.

I’m using the desktop app from master. Sorry to post so much detail, but I think the code will make easier sense with some background. This is what I have design:

There are small slits where “legs” of a speaker grill is supposed to go in and are to be bent inwards. Therefore I need to remove some pieces of the ring there. The nature of the whole thing is therefore a somewhat deeply nested structure of unions and differences.

First the whole plate, then some cutouts, but then I need to re-add material (the circle) after the cutouts and then also subtract again after that add…

So it’s like

difference(
   union(
      difference(
          union(positives…)
          negatives
       )
       postPositives…
    )
    postNegatives…
)

Actual code:

const panelThickness = 2.3

const { widthOfHp, eurorackPanel, PJ301, AlphaPot, ThreeMmLed, PowerSwitch } = require('../eurorack-lib/eurorack-lib')({
  panelThickness,
})

const jscad = require('jscad-tree-experiment')
const { difference, union } = jscad.api.booleanOps
const { translate, rotate, mirror } = jscad.api.transformations
const { cube, cylinder } = jscad.api.primitives3d
const { color } = jscad.api.color

const panelHp = 14
const width = widthOfHp(panelHp)

const middle = width / 2

// No margin
const grillY = 61 + 2
const grillX = 56 + 2

const speakerOuterDiam = 57
const speakerHoleDiam = 50

const grillMounts = () => {
  const grillXMount = 56
  const grillYMount = 41
  const grillMountLength = 7 // with margin

  let slit = union(
    cube({ size: [1, grillMountLength, 20], center: true }),
    translate([9, 9, 9], cube({ size: [1, grillMountLength, 20], center: true }))
  )

  slit = cube({ size: [1, grillMountLength, 20], center: true }) // COMMENT OUT FOR ISSUE

  return union(
    translate([-grillXMount / 2, -grillYMount / 2, 0], slit),
    translate([+grillXMount / 2, -grillYMount / 2, 0], slit),
    translate([-grillXMount / 2, +grillYMount / 2, 0], slit),
    translate([+grillXMount / 2, +grillYMount / 2, 0], slit)
  )
}

const speakerMountCircle = () => {
  return difference(
    cylinder({ d: speakerOuterDiam + 5, h: 5, $fn: 40 }),
    cylinder({ d: speakerOuterDiam, h: 5, $fn: 40 })
  )
}

const speakerHole = () => {
  return translate([0, 0, -0.01], cylinder({ d: speakerHoleDiam, h: 20, $fn: 40 }))
}

const speakerY = 45

function negatives() {
  return union(
    translate([middle, speakerY, 0], speakerHole()),
    translate(
      [middle, speakerY, 0],
      translate([0, 0, panelThickness], cube({ size: [grillX, grillY, 1], center: true }))
    ),
    translate([middle, speakerY, 0], translate([0, 0, -0.1], cube({ size: [grillX, grillY, 1], center: true }))),
    translate([middle, 90, 0], AlphaPot()),
    translate([middle - 20, 110, 0], PJ301()),
    translate([middle + 10, 110, 0], ThreeMmLed()),
    translate([middle + 20, 110, 0], PowerSwitch())
  )
}

function main() {
  return difference(
    union(
      difference(union(eurorackPanel(panelHp, { mountHoles: 4, slots: false })), negatives()),
      translate([middle, speakerY, 0], speakerMountCircle())
    ),
    translate([middle, speakerY, 0], grillMounts())
  )
}

module.exports = { main, getParameterDefinitions: () => [] }

Expected Behavior

If I use the definition of slit be a union - I get lots of fan spin and no render. If I use the simple slit everything’s fine.

Actual Behavior

desktop app loops for quite some time and then I get this gc log - I guess addPolygonTreeNodes might be the only interesting info:

> @jscad/desktop@0.7.1 dev /Users/viktor/dev/projects/OpenJSCAD.org/packages/desktop
> node node_modules/.bin/electron .


<--- Last few GCs --->

[17229:0x7fc098877800]    58356 ms: Mark-sweep 2051.2 (2117.5) -> 2051.2 (2093.0) MB, 2379.8 / 0.1 ms  (+ 0.0 ms in 0 steps since start of marking, biggest step 0.0 ms, walltime since start of marking 2380 ms) last resort
[17229:0x7fc098877800]    60641 ms: Mark-sweep 2051.2 (2093.0) -> 2051.2 (2093.0) MB, 2284.2 / 0.2 ms  last resort


<--- JS stacktrace --->

==== JS stack trace =========================================

Security context: 0x1f823fb14c9 <DedicatedWorkerGlobalScope map = 0x33c5c60d411>
    1: new Node [/Users/viktor/dev/projects/OpenJSCAD.org/packages/desktop/node_modules/@jscad/csg/src/core/trees.js:~381] [pc=0x258070c0c84c](this=0x12be0364879 <Node map = 0x33c5c6100c1>,parent=0x12be03647a1 <Node map = 0x33c5c609479>)
    3: addPolygonTreeNodes [/Users/viktor/dev/projects/OpenJSCAD.org/packages/desktop/node_modules/@jscad/csg/src/core/tree...

Specifications

• Version: 231d3c6393e6d84569d8c00cf32dfe83b85d3163 (master)
• Platform: OSX
• Environment: electron desktop app

[z3dev]

@hedefalk Thanks.

I don’t thing this design is complex, and would expect the application to render, etc. without issues. I’ll try it out later next week.

I make fairly complex designs some times, with lots of small pieces and holes. Here’s one that I created a few years back…

http://www.z3d.jp/lab/view.php?design=lab-000000050

Not sure that it will help, but sharing designs is always a learning experience. 😃

[hedefalk]

@kaosat-dev Thx! I was gonna try you suggestion now after working with something else for a bit, but for some reason it seems to be working fine now… Can’t even reproduce it seems. I guess I might have translated it a bit and at this point I’m really happy it works so I can print this thing now so I might dodge from putting too much effort in a repo case. I have also gone between master and V2 a few times and cleared caches and stuff…

Your tip might be useful if I struck something similar again though and I’ll let you know if so.

I’ll close for now, thanks a lot!