Comment by IshKebab

Comment by IshKebab 5 days ago

28 replies

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The pull request is to delete the project and open SOLIDWORKS or FreeCAD.

But don't actually delete it. It looks like a nice alternative to OpenSCAD. But like OpenSCAD it's really a niche thing for designs that are highly parametric like fasteners, gears, 3D printed boxes, etc.

Like OpenSCAD using it for normal "irregular" CAD is going to be extremely frustrating. Like editing an SVG in notepad instead of Inkscape.

I still feel like there's a unexplored space where you combine the benefits of both somehow though. Like a code-based CAD but it also has a GUI editor that stays in sync and avoids the need to type in coordinates by hand. That would be extremely difficult though.

dang 4 days ago

> The pull request is to delete the project

Ouch. Please don't attack someone's work this way. It's too aggressive and against the site guidelines: https://news.ycombinator.com/newsguidelines.html.

I'm sure you didn't intend it as an attack, but it's easy to cross into poisoning the community without meaning to. Many people have been hounded into abandoning HN because of this type of swipe, or at least into never sharing their work here. We all lose when that happens.

It's a pity, because what you wrote was otherwise a fine contribution. if you had begun your comment at the good part ("It looks like a nice alternative [etc.]") it would have been great.

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DannyBee 5 days ago

This is actually what onshape is, under the covers.

The GUI is really just using their scripting primitives, etc. You can access it the same as they can, actually.

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  • throwup238 5 days ago

    Onshape is just a GUI over the Parasolid geometric modeling kernel, the same kernel used by Solidworks [1]. Whatever their scripting primitives are, they're at best a thin wrapper over Parasolid (which is true for the entire industry - it's all Siemens Parasolid and Dassault ACIS).

    [1] https://en.wikipedia.org/wiki/Parasolid#Applications

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    • DannyBee 4 days ago

      Yes, this is all true, but the comment I responded to wanted to be able to basically code rather than GUI sometimes , but still have the GUI up to date. Because of how onshape was built it makes this very very easy. Solidworks very much does not. Fusion360 also has good enough python bindings but it's still nowhere near as easy or integrated to do this (or debug it) as onshape.

      So I'm kinda not sure what you are going for here. The fact that they are all the same kernels under the cover is sort of irrelevant. It's not that thin a layer and the layer matters a lot since it is what you get to use. It's like saying all of userspace is just syscalls. That's not what users see or interact with, the layer they interact with matters a lot to them.

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      • WillAdams 3 days ago

        For folks who are curious about this, see:

        https://cad.onshape.com/FsDoc/

        My surmise is that this is tightly coupled with Parasolid, so it wouldn't be feasible to create an implementation of this language using some other CAD kernel?

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        • DannyBee 2 days ago

          You could port it, but i don't think the geometry kernel is the hard part.

          The code for the standard library is here: https://cad.onshape.com/documents/12312312345abcabcabcdeff/w...

          (Click tab manager in the bottom left and you'll get a nicer list of the files involved)

          The actual representation is essentially dictionaries. IE transform is a functon that looks like this:

            /**
   * Construct a [Transform] using the matrix argument for rotation
   * and scaling and the vector argument for translation.
   */
  export function transform(linear is Matrix, translation is Vector) returns   Transform
  precondition
  {
      matrixSize(linear) == [3, 3];
      is3dLengthVector(translation);
  }
  {
      return { "linear" : linear, "translation" : translation } as Transform;
  }
          Fillets, for example, are a whole bunch of featurescript UI around fillet operations:

          https://cad.onshape.com/documents/12312312345abcabcabcdeff/w...

          (The underlying fillet ops are opFullRoundFillet, etc. All of this is UI to generate the parameters and highlight the results and such)

          The actual geometry ops are in geomOperations. Those are the geometry primitives you'd have to duplicate, and they are fairly standard. Fillets, holes, CSG, etc.

          It would not be a ton of work (IMHO) to have a geometry kernel that supports what they support.

          The UI related primitives, the query engine, etc, those are i think where you'd have real work to do.

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    • squeedles 4 days ago

      And both of them were written by Ian Braid, Alan Grayer, and Charles Lang (and others) in Cambridge.

      Parasolid was v1 and old school C, then they got the C++ bug like many of us at the time and did ACIS as v2.

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amelius 5 days ago

> Like editing an SVG in notepad instead of Inkscape.

Speaking of which, I would love to have parametric capabilities in Inkscape.

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  • TheTaytay 5 days ago

    I recently stumbled across cuttle.xyz, and it’s a code-based parametric vector editor. I recently did a real world art project in it and LOVED it.

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  • avhon1 4 days ago

    FWIW, the FLOSS CAD program SolveSpace can generate parametric sketches and export them as SVG files (file > export 2d view)

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    • WillAdams 4 days ago

      Is there a facility when doing this for controlling colour/fill?

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      • avhon1 3 days ago

        SolveSpace does have some ability to control the color and fill of areas. It's nowhere near as powerful as Inkscape, but enough to make simple diagrams. The exported SVGs can also be edited in Inkscape.

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        • WillAdams 3 days ago

          Nice! (if memory serves, the last time this came up that wasn't possible)

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hyperbrainer 4 days ago

> "highly paramteric like fastners, gears, 3D printed boxes"

1. These parts should probably be on McMaster. If you are not using them straight from there, you better have a _great_ reason as to why not when it comes up in the design review.

2. Solidworks has Smart Fasteners, Inventor has Spur Gear Component Generator, Sketch->Extrude->Shell takes 30 seconds, so not sure why 3D printed boxes would be faster or better with this for most stuff. Also, this stuff is easily solved by things like the component library and configurations.

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  • IshKebab 4 days ago

    > you better have a _great_ reason as to why not

    Because I don't live in America?

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    • bluGill 4 days ago

      Are you saying that you don't us McMaster because they don't ship to where you live? That seems silly - you can still download their drawings and then find an alternate source. They are a great listing of everything you might ever want to buy, but you can almost always find an alternative source.

      There is also the possibility you think because McMaster is in the US they don't have metric parts. This is wrong, a lot of engineering in the US is done in metric - nearly all big manufacturing companies went metric 40 years ago, so they have plenty of metric parts that you should work with. Of course most manufacturing is small companies that still haven't gone metric, but they also deal with metric once in a while, and in any case you wouldn't be ordering from them anyway.

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    • dymk 4 days ago

      Are ISO standard parts not used where you live? McMaster is in the US but the much of the parts and CAD are standard

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    • hyperbrainer 4 days ago

      I download and use parts dimensioned in metric to ISO standards all the time...

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aaronblohowiak 5 days ago

>I still feel like there's an unexplored space where you combine the benefits of both somehow though. Like a code-based CAD but it also has a GUI editor that stays in sync and avoids the need to type in coordinates by hand. That would be extremely difficult though.

I think you can do this if the data representation of operations and values is human readable. The simplest implementation would restrict the language/data format to operations representable in the gui.

Unlike trying to solve the "visual programming" problems, we don't need or desire Turing completeness.

Very interesting indeed!

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prennert 4 days ago

Ha! Since you mention SVG, there is a trick!

Draw your free-hand shape in Inkscape, export to SVG, import it in FreeCAD and go from there.

I used that trick to trace a part from an image and it worked surprisingly well. Not very efficient compared to commercial tooling, but despite the clumsiness its fairly intuitive and free.

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jfindley 4 days ago

All the good commercial parametric CAD apps have an API that allow you to define models programatically to avoid repitition, or do more complicated things like ensure gear ratios are exactly correct. I'm not sure I entirely understand what you're getting at with the "stays in sync" part though.

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NonHyloMorph 5 days ago

Are you aware of Rhino 3D with grasshopper?

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