Heads Up. New file format AMF to replace STL?

Hey guys

Maybe someone will find this interesting....

[www.physorg.com]

This was supposed to happen sooner or later...

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... is an XML-based format designed to ...

obligatory:
The Case Against XML


It would really have been nice if someone would have invested the effort to develop a decent binary file format instead.

json or one of the json derivatives like bson would be a decent drop in replacement for the xml format while preserving the rest

11. Compression and distribution
An AMF shall be stored either in plain text or be compressed. If compressed, the compression shall be in ZIP archive format [4] and can be done manually or at write time using any one of several open compression libraries, such as [5].
Both the compressed and uncompressed version of this file will have the AMF extension and it is the responsibility of the parsing program to determine whether or not the file is compressed, and if so to perform decompression during read.
Additional files may be included in the ZIP archive, such as manifest files and electronic signatures. However only the AMF file with the same name as the archive file will be parsed. Absence of a file with that name will constitute an error.
This standard does not specify any explicit mechanisms for ensuring data integrity, electronic signatures and encryptions.

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Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse

Well, compression only helps with the excessive storage requirement for xml documents.

In our case (and most cases if you believe the most popular critics) the major issue is the processing time required to parse it. Doing that on a AVR is out of the question and even with something like ARM, PIC32 or Propeller we would sacrifice a major junk of performance.

Also if you want to store vertices you are better of with a flat storage model.
XML would make sense be used to describe object with CSG for example but to replace STL?

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ElectricMucus
obligatory:
The Case Against XML

wow. That document added nothing I didn't already know about XML and then rambled on about Word douments being saved in HTML.

I agree that there's no reason a binary format isn't used. Sticking with XML would only be useful for human readable / human editable files. I don't think that's going to come up too often

taraba Wrote:
-------------------------------------------------------
> > obligatory:
> The Case Against XML
>
>
> wow. That document added nothing I didn't already
> know about XML and then rambled on about Word
> douments being saved in HTML.

I don't think it is supposed to accomplish anything more.

> I agree that there's no reason a binary format
> isn't used. Sticking with XML would only be useful
> for human readable / human editable files. I don't
> think that's going to come up too often

agreed.
as said before, it would make sense to describe primitives in 3d construction on a higher level like CSG or similar, use it as a format for parametric modeling and the liking, but that isn't the case with STL files.

I blame CS academia for this, solutions are thought of for abstract constructs instead of real world application and if implementation isn't feasible it is ignored.

There is one really nice feature of AMF - the ability to have vertex normals! This alone could greatly decrease the size of mesh files, but at the expense of greatly increasing the amount of processing power needed to 'slice' a given mesh if the normals are to be used for curve generation.

I've wanted vertex normals in STL for ages so that I could get decent looking output from POV-Ray when rendering meshes exported from a CAD program...

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[haveblue.org]

Whatever about the shortcomings of an XML format, doesn't this new format at least have the virtues that it facilitates:

1. colour specification, and
2. material specification?

I imagine these features may become important for Reprap users at some stage down the line - e.g. when colour-printing is implemented.

Personally, I think it's an interesting development.

Link: Additive manufacturing file format (Wikipedia)