[x3d-public] Wishlist for view3dscene

[Joseph D Williams]

➢  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.


➢ No need for text parsing.

There is always a need for text parsing when authortime is text.   

Of course that and other stuffs is right for the runtime ----- but not for the authortime. Yes, even though the authortime might intrude into the runtime, there is a time when the authorinter acts directly with the code and tool implementers should do all they can to make it easy for the author (code generator).  
And, sorry about the all this text parsing needing to be done as an apparent dissatisfier, but x3d is primarily a text format for people not necessarily directly for machines. Sure there are several other ways to encode x3d, but text is the main and only real spec way since somebody else specs the blobs and we just want to author and deliver using them. I hope your browser will allow me to import runtime forms that I can also edit at authortime. Hopefully there are some special defined blobs that I can import and edit in x3d user code and then export runtime blobs of this type for delivery. 

I guess still my prime example is the difference between how skeleton animation joint to vertex bindings and weights are done in X3D Joint versus typical runtime storage, like you seem to cite above. We don’t care about the idea that under-the-covers is so much easier for the implementer, and so ‘efficient storage’ is directive and it really doesn’t, or we can’t see how it could, impact the actual content creator.   
Thanks, 
Joe
  

From: Joseph D Williams
Sent: Saturday, February 11, 2023 1:08 PM
To: Michalis Kamburelis; Brutzman, Donald (Don) (CIV)
Cc: X3D Public Mailing List (x3d-public at web3d.org)
Subject: RE: Wishlist for view3dscene

"""
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).
"""

Not surprizing because there is nothing in Hanim that requires that precision.
These are all zero. Show example. 



From: Michalis Kamburelis
Sent: Friday, February 10, 2023 5:13 AM
To: Brutzman, Donald (Don) (CIV)
Cc: Joseph D Williams; X3D Public Mailing List (x3d-public at web3d.org)
Subject: Re: Wishlist for view3dscene

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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