[x3d-public] x3dom nurbs support

[Andreas Plesch]

These notes seem to cover it but a bit too concisely:

http://www.cgeo.ulg.ac.be/CAO/CAD_06.pdf
On Sat, Sep 29, 2018 at 4:10 PM GPU Group <gpugroup at gmail.com> wrote:
>
> Andreas
> swept and swung are in The Nurbs Book (and not too hard - a 2D curve, then extrude that curve in a few different ways. Swept: along an arbitrary 3D curve,could be a curbs curve. Swung: around some line/axis lying in the plane of the curve)
> -Doug
>
>
> On Sat, Sep 29, 2018 at 10:34 AM Andreas Plesch <andreasplesch at gmail.com> wrote:
>>
>> Based on the initial Ayam x3dom Nurbs node support for PatchSurface
>> and TrimmedSurface, I am working on more complete and animation
>> capable Nurbs component implementation in my x3dom NURBS branch.
>>
>> Here are examples of working nodes:
>>
>> https://rawgit.com/andreasplesch/x3dom/Nurbs/test/functional/nurbs/inline.html
>>
>> I added NurbsCurve and the interpolators. In addition, the web worker
>> code can now be bundled, and is optimized to support animation of
>> control points and weights which do not require retriangulation. This
>> makes the AnimatedNurbsPatchSurfaceHead example borderline ok to
>> animate on a regular desktop but also shows the limits off CPU (via
>> js) only animation although there is additional room for further
>> optimization (for example using transferables for communicating with
>> workers). A more substantial improvement has to come from shaders.
>>
>> I think most Nurbs examples from Basic Archive are working, after
>> fixing them as previously reported.
>>
>> Some details: The Curve tessellation is strictly subdivision following
>> the tessellation hints as speced. The Ayam surface tessellation is
>> adaptive with a threshold being influenced by the tessellation hints
>> as well.
>> The tessellation (and animation by deformation) will spawn web
>> workers/threads. The maximum number of workers is aggressively set and
>> can max out CPUs. I probably should expose the number in a scene
>> setting to scenes. It is defined in the x3dom-nurbs-pool.js file.
>> Vertex animation does not recalculate automatic normals currently for
>> performance but that could be added.
>>
>> The SweptSurface and SwungSurface are not implemented and I do not
>> have a good idea how to.
>> The NurbsTextureCoordinate is not implemented. Is it used ? Are the
>> default texture coordinates usually ok ?
>>
>> Any comment or feedback welcome,
>>
>> -Andreas
>>
>>
>>
>>
>> --
>> Andreas Plesch
>> Waltham, MA 02453
>>
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-- 
Andreas Plesch
Waltham, MA 02453