[x3d-public] Over next several weeks, I will be ramping up

[John Carlson]

 Vince, we can go for lowest hanging fruit first (meshes to STL, which i
have somewhat done), and then proceed to more abstract geometry (spheres,
cones, cylinders, extrusions, 2D, NURBS).  I am particularly interested in
converting spheres to other shapes.

But yeah, NURBS does need to be done in X3DOM, it appears in the wish list.

I’m not pursuing browser implementations at this time, initial focus will
be on nodejs, ES6, then probably TypeScript.  Later, I will probably port
to X3DJSONLD for browser implementations.   Particularly, i would like for
someone to review early code for correctness.

Have you looked at brython in the browser?

There is a good video on NURBS from Bill Joy from UC Davis describing NURBS
algorithms.   Thumbs up, and free!

Oh, i like to think of myself as a high-powered programmer ;) who stayed up
too many late nights (think of the opposite of Ben Franklin’s quote). I
took all available 3D computer graphics courses at my school (1
undergraduate 2 or so graduate courses).  Of course, you probably don’t
want me programming radiosity or the rendering equation at this point in my
life.  I’m not interested in programming lighting equations, just pure
geometry.   People like Holger and Yvonne have better shading skills.

And yes, i have experience tessellating spheres, the way i think of it is a
NxN grid of triangles. (breaking the quadrilaterals into 2 triangles), then
“wrapping” the grid around a “sphere” and offsetting the vertices in the
vertex shader.  However, grid for spheres produced from Blender are better
than mine and we could probably export a sphere from that and convert to
JSON.    I feel confident taking abstract grids and converting them into
shapes in a vertex shader.

I’m not sure if you’re a JavaScript programmer or not.  I have the goal of
getting the JavaScript tessellation of a sphere in the new code in a couple
of weeks.

I understand that parametric modeling may be preferable, but my goal is
STL, so i can 3D print my orbitals!

Since I’ve tessellated spheres, I can probably do the cone and cylinder.

I heard a rumor that the Castle Engine folks are working on a Pascal to
WASM compiler of X3D, I’m giving them $5 a month.  Maybe I should increase
that.

If you can create necessary geometry with opencascade, that would awesome.
My first choice would be Blender.

On Tue, Dec 20, 2022 at 6:46 AM vmarchetti at kshell.com <vmarchetti at kshell.com>
wrote:

> I do not think any of those libraries implement tesselation, if by
> tesselation you mean a function that you can pass a high-level description
> of a geometry , a description being a set of parameters for a  primitive
> shape, or a larger set for a parametrically defined geometry such as NURBS,
> and that function returns some kind of mesh. It looks like you need some
> high powered code such as OpenCascade, C++ with Python binding available. I
> periodically try to explore whether WebAssembly is a viable way to make
> this code base work in the browser, with no positive results so far.
>
> In short, I would judge that in-browser tesselation is not yet a useful
> option to pursue.
>
> No browser pursuit right now, just STL.  Let’s not kill my system yet, i
need to save some money for a new one, a new car, etc.

Vince Marchetti
>
>
> On Dec 20, 2022, at 6:06 AM, John Carlson <yottzumm at gmail.com> wrote:
>
> <image.png>
>
> The Stereo Lithography (STL) export converter from X3D JSON to STL looks
> like low hanging fruit. I just need to find some good tesselation code in
> ECMAScript. I already have a basic framework. Can anyone recommend A-Frame,
> Three.js, Babylon.js, Unity, X3DOM or X_ITE code for doing tesselation, or
> is it built into WebGL?  Meanwhile, I will be working on meshes and
> creating a project, etc.
>
> On Tue, Dec 20, 2022 at 4:45 AM John Carlson <yottzumm at gmail.com> wrote:
>
>> Over the next several weeks, I will be ramping up for potential return to
>> work, testing out CTS coping skills (laying on a different side, taking
>> breaks), computer hygiene, sleeping hygiene etc.
>>
>> My wife has given me the thumbs up to return to work remotely.
>>
>> So if there's any X3D tasks, I should be able to pick some of them up, I
>> will look at the wishlist.
>>
>> BTW, has anyone attached Gmail to GPT-3?
>>
>> Everyone have a merry xmas and happy new year.
>>
>> Thanks!
>>
>> John
>>
>
>
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