V2 feedback

[gilboonet]

Hello, I'm updating my 2 axis slicer, replacing my functions by scission() and project(). And I'm having an odd error with project(). My volume is centered, and when I try to slice on the Y axis on some places that are <0 I have :

Error : the given points must define a closed geometry with three or more points
Line: 555"

My test volume is symetric, and when I slice symetrically, it works. But what is odd is that at the left of the <0 part of the volume I can also slice. For the moment I will use my script with scission() and my pseudo-projection function vol2surf().

There's also another thing, when I use the script for some time, adding, moving and removing slices and also switching from 3d to 2d, the script hangs and I need to reload the page, sometimes, the script loads without the parameters, and I need to reload it again. There's maybe a memory issue, but I only have 8 Gb of RAM.

I'm also starting to create parametric furniture which is my main goal and was impossible to do as long as there were those T-junctions errors that are now overcome, and it looks promising. For the moment I'm exporting a furniture model to .STL, then import it when I want to slice it.

[z3dev]

@gilboonet thanks for the feedback.

I have a few questions about the process of slicing.

Are you creating the slices? How?

That error is from the geom2.fromPoints() when less than three points are provided. There may be an edge case where the projection created an invalid set of points.

Can you provide the stack trace? It should be in the browser console.

[gilboonet]

@z3dev Yes I'm creating the slices for each axis from intersection of the model and a translated cuboid, then I create notches made from intersections of those slices, 1st axis slices have top half of those intersections subtracted and 2nd axis slices have bottom half, so they fit. Code is :

const main = (params) => {
  const sc = 1, ep = params.ep *2

	//const vv = require('./' + params.v + '.obj')
	const vv = require('./' + params.v)
	
  const vol = center({}, rotateX(degToRad(90), vv))
  //const vol = center({}, vv)
  
  let r = [], rH = [], rV = []
  let bV = measureBoundingBox(vol)

	// Recup parametres
  const pv = Object.values(params)
  const lH = pv.slice(0,10).filter(Number).map(x => (x-50)/100)
  const lV = pv.slice(10,20).filter(Number).map(x => (x-50)/100)
  
	// 1°) Traverses en X (H)
  fH = bV[1][0] - bV[0][0]
  mH = (bV[1][0] + bV[0][0]) / 2
  var trH = cuboid( {
		size: [ ep, 1+bV[1][1]- bV[0][1], 1+bV[1][2] - bV[0][2] ]} )
	for (let i = 0; i < lH.length; i++){
		var t = intersect(vol, translateX(fH * lH[i], trH))
		if (t.polygons.length > 0)
			rH.push(t)
	}

	// 2°) Traverses en Y (V)
	fV = bV[1][1] - bV[0][1]
	mV = (bV[1][1] + bV[0][1]) / 2
	var trV = cuboid( {
		size: [ 1+ bV[1][0] - bV[0][0], ep, 1+ bV[1][2] - bV[0][2] ]} )	
	for (let i = 0; i < lV.length; i++){
		var t = intersect(vol, translateY(fV * lV[i], trV))
		if (t.polygons.length > 0)
			rV.push(t)
	}
	
	// 3°) Entrecroisement
	var ur = union(intersect(union(rH), union(rV)));
	var tmp = scission(ur)
	console.log(tmp.length) 
	var eS = [], eH = [], eV = [];
	for(let i=0; i< tmp.length; i++){
		let p = tmp[i];
		let b = measureBoundingBox(p), 
				//d = vec3.subtract(b[1], b[0]);
				d = [b[1][0]-b[0][0], b[1][1]-b[0][1], b[1][2]-b[0][2]];
		let c1 = translate([b[0][0], b[0][1] + ep/2, b[0][2]], 
					cuboid({size: [d[0], d[1]*2, d[2]]}));
		let c2 = translate([b[0][0] + ep/2, b[0][1], b[1][2]], 
					cuboid({size: [d[0]*2, d[1], d[2]]}));
		
		eH.push(intersect(tmp[i], c1));
		eV.push(intersect(tmp[i], c2));
	}
	
	rH = rH.map(x=> subtract(x, eV));
	rV = rV.map(x=> subtract(x, eH));

	
	if(params.mode == '3'){ // 3d
		r.push(colorize([0,1,0,0.8], translateX(-70, subtract(vol, [rH,rV]))));
		
		r.push(colorize([0.5,0.0,0], translateX(-70, rH.shift())));
		if(rH.length > 0){
			r.push(colorize([1,0,0], translateX(-70, rH)));
		}
				
		r.push(colorize([0,0,0.5], translateX(-70, rV.shift())));
		if(rV.length > 0){
			r.push(colorize([0,0,1], translateX(-70, rV)));
		}
	} else { // 2d
		var dk = Math.max(fV, fH) *1.1
		for(let ih = 0; ih < rH.length; ih++){
			let b = measureBoundingBox(rH[ih]);
			//r.push(translateX(dk *ih, union(vol2surf(rH[ih], 'x', b[0][0]))))
			r.push(translateX(dk *ih, union(project({axis:[1,0,0]}, rH[ih]))))
		}
		for(let iv = 0; iv < rV.length; iv++){
			let b = measureBoundingBox(rV[iv]);
			//r.push(translate([dk *iv, -dk - params.dky], union(vol2surf(rV[iv], 'y', b[0][1]))))
			r.push(translate([dk *iv, -dk - params.dky], union(project({axis:[0,1,0]}, rV[iv]))))
		}
	}
		
	return r;
}

Stack trace is maybe (I'm using Firefox) :

fromPoints blob:https://openjscad.xyz/333c3c92-e91a-42a7-8b4b-7dc2cdc255ce:555
    m blob:https://openjscad.xyz/333c3c92-e91a-42a7-8b4b-7dc2cdc255ce:1389
    map self-hosted:224
    projectGeom3 blob:https://openjscad.xyz/333c3c92-e91a-42a7-8b4b-7dc2cdc255ce:1389
    n blob:https://openjscad.xyz/333c3c92-e91a-42a7-8b4b-7dc2cdc255ce:1389
    map self-hosted:224
    project blob:https://openjscad.xyz/333c3c92-e91a-42a7-8b4b-7dc2cdc255ce:1389
    main blob:https://openjscad.xyz/333c3c92-e91a-42a7-8b4b-7dc2cdc255ce line 38 > Function:137
    instanciateDesign blob:https://openjscad.xyz/333c3c92-e91a-42a7-8b4b-7dc2cdc255ce:5
    rebuildSolids blob:https://openjscad.xyz/333c3c92-e91a-42a7-8b4b-7dc2cdc255ce:8
    onmessage blob:https://openjscad.xyz/333c3c92-e91a-42a7-8b4b-7dc2cdc255ce:11

[gilboonet]

@z3dev In order to simplify my process, I'm trying to directly use project to make the slices, and I'm beginning with an example, but I don't understand how to make several slices. First I used origin but it does not seem to work, then I'm translating the oldObject and it does not work, everytime I have the same slice.
here's my latest code :

const jscad = require('@jscad/modeling')
const { ellipsoid } = jscad.primitives
const { project } = jscad.extrusions
const { translateX, translateY, translateZ, center } = jscad.transforms
 
const main = () => {
  const vol = ellipsoid({radius: [10, 15, 20], segments: 12})
  
  let r = []
  for(let i = 0, dx = -80; i < 50; i += 10, dx += 40){
    r.push(
     translateX(dx, center({}, project({axis:[1,0,0]}, translateZ(i, vol))))
    )
  }
  
  r.push(vol)
  return r
}
 
module.exports = { main }

Maybe do I need to translate the object prior to the projection ?

[z3dev]

The origin and axis create a plane, which passes through the origin and lays facing up the axis. Just like the grid passes through [0,0,0] and faces up the Z axis.

The plane can be placed anywhere, which makes it easy to project different views of the 3D shape. No rotation or positioning of the 3D shape is required.

[z3dev]

The WHOLE 3D shape is projected to 2D. If you want to project a ‘slice’ then use the booleans to make a ‘slice’, and project the ‘slice’.

[gilboonet]

@z3dev I think I get it now, it means that there's no simpler way to make the slices than what I already did at first.

[hrgdavor]

@gilboonet here is sth unrelated to this topic, but sending anyway

I know you like folding stuff, so here is a cool project

https://hackaday.com/2021/10/14/hacking-an-ikea-lampshade-into-a-stunning-dichroic-lamp/

[gilboonet]

@hrgdavor Thank you, that's very nice. It's not that I like folding things but it's a process I use to build them with cardboard