siggraph 2010 - collada bof - 2 - extensions process

8/9/2019 SigGraph 2010 - Collada BOF - 2 - Extensions Process

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Extensions Pr

Rmi Arnaud

Chief Software Architect, Screampoint Intl.

Mark Barnes

Sr Software Architect, Biodroid Productions Lda.

COLLADA Work Group Chairman, The Khronos Group


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Agenda

COLLADA usage model

COLLADA extension mechanism

Extensions by example

NEW- Khronos WG COLLADA extension process

Questions?


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COLLADA extensions usage model

COLLADA users required extensions

o project/user specific meta data carried from DCC to ApplicationExport user defined properties of Max nodes into an extra element of the corresponding COLLADA nod

Max/Maya plug-ins.

COLLADA tool vendors required extensions

o tool can refine COLLADA definition with additional parametersCamera XSI extension extends the COLLADA common representation

https://collada.org/mediawiki/index.php/Camera_XSI_extension

o tool want to provide an alternative representation Alternative shader languages (Cg, GLSL, HLSL)Renderman shader code as alternative http://www.cs.utexas.edu/ftp/pub/techreports/honor

whiteford.pdf

o using COLLADA as a tool native format extensions replacing proprietary format

COLLADA is the basis format of LightWave CORE , with extensions added by the NewTek engineerinhttp://www.newtek.com/lightwave/core/


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COLLADA extensibility model

COLLADA is a declarative data model

Schema includes extensions mechanisms

Adding

Declarations represent new features

Replacing

Declarations represent alternative techniques (descriptions)

Combining

Adding and Replacing recursively


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Extension Mechanisms

profiles

Replace one description with another

Choose the best profile

types

Add declarations to most everything

A bag of techniques

Adding choices can be recursive

semantics

Add new streams to data flows


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COLLADA extension mechanis


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COLLADA extension mechanis

or or primitive choice

0 0 0 1 1 0 .

Standard semantics defined in COLLADA spec. 5-40


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Extension rules COLLADA spec. 3-6


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Example Extension - bump

11

000

00

11..

0.11

...

0 0 0 10 0 0 1

8.0

0 0 0 10

0 0 0 110

11

00


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Example Extension - bump

...

0 0 0 10 0 0 1

8.0

0 0 0 10

0 0 0 110

11

00

11

000

00

11..

0.11


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.

.

true0 0 0

10.000000

Example Extension - LOD

Ignoring resultin flickering (z-fighting)


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Example improved LOD extension

true

0 0 0

.

10.000000

Ignoring


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Need for multi-vendor extensions

http://www.okino.com/conv/exp_collada_extensions.htm

1

1

1

!!!


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COLLADA Extension Process Summary

Visit https://collada.org/mediawiki/index.php/Portal:Extension

Determine if you need to create an extension

Create your extension by following the guidelines

Submit draft to COLLADA work group for review

Get feedback from the COLLADA specification working group

Receive Published stamp of approval

V


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Visit

C


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Create


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Is there already an extension that does what I wa

Can it be used instead of writing a new one?

reuse of an existing specification

or promoting single-vendor COLLADA extensions to multi-vendor or Khronos-appr

ask the COLLADA Working Group chair whether anyone has already defined related

[email protected]

Sh ld th t i b Kh d


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Should the extension be Khronos-approved, muor single vendor?

If the functionality being designed is going to be used by multiple applications - as most

idea to agree on a single extension with other developers - this makes it easier for vendor

development of the extensions, and better interoperability for end-users.

If the functionality is well-understood, it may be appropriate to define a Khronos-approvis the most "blessed" category of extension; it goes through the entire standards process,

the working group, but remains optional functionality.

Khronos-approved extensions are IP-safe, royalty-free licence. Khronos contributing meKhronos-approved extensions. Vendor or multi-vendor extensions may not be. Khronos-

extensions are as good as features added to the specification, it is a fast path for adding fespecifications.

Some extensions may have to remain proprietary and would therefore not be published.

useful to designers of proprietary extensions however.

D


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Determ

ine

D


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Determ

ine

D


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Determ

ine

E
https://collada.org/mediawiki/index.php/Morph_weights_EXT_extension


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Examp

le
https://collada.org/mediawiki/index.php/Morph_weights_EXT_extension


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Questions?

siggraph 2010 - collada bof - 2 - extensions process

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