[x3d-public] quaterntion lib., was: errors in convertJsonToStl.js

Mon Jun 4 06:28:01 PDT 2018

What I need for STL is to unwind all the transforms into actual
coordinates.   STL has no concept of transforms.

John

On Mon, Jun 4, 2018, 8:47 AM Andreas Plesch <andreasplesch at gmail.com> wrote:

> x3dom has a pretty complete matrix et al. math library which includes
> quaternions:
>
> https://github.com/x3dom/x3dom/blob/master/src/fields.js#L1754
>
> Its invert methods looks the same as yours.
>
> I am not sure if inverting a quaternions is identical to inverting the
> 4x4 rotation matrix derived from a quaternion, or if that is what you
> need for stl.
>
> -Andreas
>
> > Date: Mon, 4 Jun 2018 03:18:40 -0400
> > From: John Carlson <yottzumm at gmail.com>
> > To: X3D Graphics public mailing list <x3d-public at web3d.org>
> > Subject: Re: [x3d-public] errors in convertJsonToStl.js
> > Message-ID: <5b14e7cf.1c69fb81.b0537.d319 at mx.google.com>
> > Content-Type: text/plain; charset="utf-8"
> >
> > I looked at my quaternion code today, and at quaternions and rotations
> on the web.  I am not quite sure how I came up with the code I did (I saw
> some video). I think I watched the wrong video, or I was smoking anxiety
> that day.  Currently, my converter converts lots of stuff to a plane, it
> looks like (see SuperCobra).
> >
> > Can anyone point me to a reasonable open source implementation of
> quaternion rotations in JavaScript, Java, C or C++?  X_ITE or X3DOM?
> Ideally, the quaternions would fit into a 4x4 matrix stack, which is how I
> learned how to do transforms (I am not doing a perspective transform that I
> know of, so perhaps 3x3 is good enough).  Yes, I know that other
> implementations are probably more efficient. I?d like to try to get 4x4
> transforms working first before optimizing.  4x4 transforms are NOT a
> requirement, however, just a nice to have.
> >
> > John
> >
> >
> > Sent from Mail for Windows 10
> >
> > From: John Carlson
> > Sent: Saturday, May 20, 2017 2:20 AM
> > To: Don Brutzman; X3D Graphics public mailing list
> > Subject: RE: errors in convertJsonToStl.js
> >
> > New versions of X3D JSON, STL and PLY interoperability are here:
> >
> >
> https://github.com/coderextreme/X3DJSONLD/blob/master/src/main/node/convertJsonToStl.js
> >
> https://github.com/coderextreme/X3DJSONLD/blob/master/src/main/node/convertPlyToJson.js
> >
> https://github.com/coderextreme/X3DJSONLD/blob/master/src/main/node/convertStlToJson.js
> >
> > This mostly works with Indexed geometry.? I don?t handle PLY texture
> coordinates yet.
> >
> > Contributions are welcome, particularly JSON to PLY?
> >
> > John
> >
> >
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> > ------------------------------
> >
> > Message: 3
> > Date: Mon, 4 Jun 2018 06:48:24 -0400
> > From: John Carlson <yottzumm at gmail.com>
> > To: X3D Graphics public mailing list <x3d-public at web3d.org>
> > Subject: Re: [x3d-public] errors in convertJsonToStl.js
> > Message-ID: <5b1518f7.1c69fb81.ed8cb.38a4 at mx.google.com>
> > Content-Type: text/plain; charset="utf-8"
> >
> > Well, I ?fixed? my code, but would appreciate a second pair of eyes
> looking at it.  Essentially, I added an inverse quaternion to the transform
> ?stack? (now not quite a stack).
> >
> >
> https://github.com/coderextreme/X3DJSONLD/blob/master/src/main/node/matrix.js
> >
> https://github.com/coderextreme/X3DJSONLD/blob/master/src/main/node/convertJsonToStl.js
> >
> > search for quaternion.
> >
> > If you hook up the X3DJSONLD web server, you can search for ?LightsOn?
> in X3DJSONLD and look at the JSON file  at /c/x3d-code/
> www.web3d.org/x3d/content/examples/Savage/? (set up Cygwin/MingW, node.js
> etc, create symbolic link).
> >
> > It should convert to STL automatically I think. To convert back to JSON
> (and display as a green surface), press the here above the STL output pane.
> >
> > But really, just a review of the quaternion code should be sufficient.
>  There?s probably an issue with the viewpoint in the example (STL doesn?t
> have viewpoints, and I don?t think I?ve taken the time to introduce the
> necessary transforms).
> >
> > Thanks,
> >
> > John
> >
> >
> > Sent from Mail for Windows 10
> >
> > From: John Carlson
> > Sent: Monday, June 4, 2018 3:18 AM
> > To: X3D Graphics public mailing list
> > Subject: RE: errors in convertJsonToStl.js
> >
> > I looked at my quaternion code today, and at quaternions and rotations
> on the web.? I am not quite sure how I came up with the code I did (I saw
> some video). I think I watched the wrong video, or I was smoking anxiety
> that day. ?Currently, my converter converts lots of stuff to a plane, it
> looks like (see SuperCobra).
> >
> > Can anyone point me to a reasonable open source implementation of
> quaternion rotations in JavaScript, Java, C or C++?? X_ITE or X3DOM?
> Ideally, the quaternions would fit into a 4x4 matrix stack, which is how I
> learned how to do transforms (I am not doing a perspective transform that I
> know of, so perhaps 3x3 is good enough).? Yes, I know that other
> implementations are probably more efficient. I?d like to try to get 4x4
> transforms working first before optimizing.? 4x4 transforms are NOT a
> requirement, however, just a nice to have.
> >
> > John
> >
> >
> > Sent from Mail for Windows 10
> >
> > From: John Carlson
> > Sent: Saturday, May 20, 2017 2:20 AM
> > To: Don Brutzman; X3D Graphics public mailing list
> > Subject: RE: errors in convertJsonToStl.js
> >
> > New versions of X3D JSON, STL and PLY interoperability are here:
> >
> >
> https://github.com/coderextreme/X3DJSONLD/blob/master/src/main/node/convertJsonToStl.js
> >
> https://github.com/coderextreme/X3DJSONLD/blob/master/src/main/node/convertPlyToJson.js
> >
> https://github.com/coderextreme/X3DJSONLD/blob/master/src/main/node/convertStlToJson.js
> >
> > This mostly works with Indexed geometry.? I don?t handle PLY texture
> coordinates yet.
> >
> > Contributions are welcome, particularly JSON to PLY?
> >
> > John
> >
> >
> >
> > -------------- next part --------------
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>
>
> --
> Andreas Plesch
> Waltham, MA 02453
>
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