[x3d-public] Wishlist for view3dscene

[John Carlson]

Not sure how feasible this is with Pascal, etc.   Perhaps consider
scientific or engineering notation with exponents.

In most cases i see, extending precision significantly increases file size,
and makes it harder to do round trips.

I don’t know if there’s a JavaScript or Python solution for this.

Perhaps we should not implement number types in our synthesized programs,
and keep numbers and arrays as strings.   Then we have to ask what is done
in glTF.

John

On Fri, Feb 10, 2023 at 7:13 AM Michalis Kamburelis <
michalis.kambi at gmail.com> wrote:

> Thanks, and sorry for a delay in answering!
>
> The "description" field has been added to texture nodes and few more,
> as you can see in another thread on x3d-public :)
>
> As for digits precision when saving: it's not so easy, in general it's
> (one of) the problems that come from X3D using text representation for
> floats in per-vertex data. Namely, if we cut the saved numbers to 4
> decimal places, I'm 90% sure that I will get a valid bugreport from
> someone:
>
> """
> Hey, my stuff no longer works! My models (in glTF, X3D, whatever) have
> vertexes at coordinates like Z = 0.00001, 0.00002, 0.00003. And now,
> after processing and saving to X3D using your tools, they are all
> equal zero, resulting in bugs (things start to fight in Z buffer).
> """
>
> Surely we could add a configuration option for it, but it feels
> counter-productive, when my recommendation to everyone would be still
> "use the maximum precision, to be safe". I would add a feature that I
> explicitly say should not be used.
>
> In the end, the longer text representation for numbers only hurts the
> file size. And I don't believe we can really fix it by outputting less
> digits. The right solution is storing per-vertex data in a binary
> blob, when each float is binary 4 bytes, so it's
>
> - efficient storage
> - efficient reading by X3D implementation to a "float[] array", no
> need for text parsing.
>
> Regards,
> Michalis
>
>
>
>
> śr., 28 gru 2022 o 21:00 Brutzman, Donald (Don) (CIV)
> <brutzman at nps.edu> napisał(a):
> >
> > Hi Michalis. Joe and I are really enjoying the many excellent features
> of view3dscene.
> >
> >
> >
> > Here are some suggested refinements and improvements.
> >
> >
> >
> > View3dscene converter: round off significant digits, rather than 10+
> decimal places.  (For example, suggested values in HAnim spec go to 4
> decimal places.
> >
> >
> >
> > View3dscene: note that we have added ‘description’ field to many nodes
> in X3D4, including ImageTexture.
> >
> > 1 warnings:
> > X3D: Unknown X3D field name (unhandled X3D XML attribute) "description"
> in node "ImageTexture"
> > Scene URL: "C:\x3d-code\www.web3d.org
> \x3d\content\examples\HumanoidAnimation\Skin\JoeSkeletonSkinSiteSaluteWalk.x3d".
> > Use "File->View Warnings" menu to view these warnings again.
> >
> >
> >
> > Coming soon: import test of three models in HAnim Motion specification.
> >
> >
> https://www.web3d.org/documents/specifications/19774/V2.0/MotionDataAnimation/MotionDataAnimation.html
> >
> >
> >
> > Again thanks for great work.
> >
> >
> >
> > all the best, Don
> >
> > --
> >
> > Don Brutzman  Naval Postgraduate School, Code USW/Br
> brutzman at nps.edu
> >
> > Watkins 270,  MOVES Institute, Monterey CA 93943-5000 USA
> +1.831.656.2149
> >
> > X3D graphics, virtual worlds, Navy robotics https://
> faculty.nps.edu/brutzman
> >
> >
>
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