COLLADA

COLLADA

Filename extension	.dae
Internet media type	model/vnd.collada+xml
Developed by	Sony Computer Entertainment, Khronos Group
Initial release	October 2004
Latest release	1.5.0 August 2008
Type of format	3D computer graphics
Extended from	XML
Website	collada.org

COLLADA is a COLLAborative Design Activity for establishing an interchange file format for interactive 3D applications. COLLADA is managed by the not-for-profit technology consortium, the Khronos Group.

COLLADA defines an open standard XML schema for exchanging digital assets among various graphics software applications that might otherwise store their assets in incompatible file formats. COLLADA documents that describe digital assets are XML files, usually identified with a .dae (digital asset exchange) filename extension.

History

Originally created by Sony Computer Entertainment, it has since become the property of the Khronos Group, a member-funded industry consortium, which now shares the copyright with Sony. Several graphics companies collaborated with Sony from COLLADA's beginnings to create a tool that would be useful to the widest possible audience, and COLLADA continues to evolve through the efforts of Khronos contributors. Early collaborators included Alias Systems Corporation, Criterion Software, Autodesk, Inc., and Avid Technology. Dozens of commercial game studios and game engines have adopted the standard.

Tools and compatibility

COLLADA was intended originally as an intermediate format for transporting data from one digital content creation (DCC) tool to another. Applications exist to support that usage for several DCCs, including Maya (using ColladaMaya); 3ds Max (using ColladaMax); Poser (v.7.0); LightWave 3D (version 9.5); Cinema 4D (MAXON); Softimage|XSI; Side Effect's Houdini; MeshLab; GPure; CityScape, CityEngine, SketchUp, Blender, modo and Strata 3D. COLLADA.dae files can be used in Adobe Photoshop software since version CS3. Game engines, such as the Unreal engine, Torque 3D, and Unity (game engine) have also adopted this format.

Two open-source utility libraries/projects are available to simplify the import and export of COLLADA documents: the COLLADA DOM library and the OpenCOLLADA project. The COLLADA DOM is generated at compile-time from the COLLADA schema. It provides a low-level interface that eliminates the need for hand-written parsing routines, but is limited to reading and writing only one version of COLLADA, making it difficult to upgrade as new versions are released. The OpenCOLLADA project provides the next generation plugins for 3ds Max & Maya and the sources of utility libraries which were developed for the plugins.

An additional open-source utility library is available from Feeling Software: FCollada. In contrast to the COLLADA DOM, Feeling Software's FCollada provides a higher-level interface. FCollada is used in ColladaMaya, ColladaMax, and several commercial game engines. The development of the open source part was discontinued by Feeling Software in 2008.

However, some applications have adopted COLLADA as their native format or as one variety of native input rather than simply using it as an intermediate format. Google Earth (release 4) has adopted COLLADA (1.4) as its native format for describing the objects populating the earth. Users can simply drag and drop a COLLADA (.dae) file on top of the virtual Earth. Alternatively, Google SketchUp Pro can also be used to create.kmz files, a zip file containing a KML file, a COLLADA (.dae) file, and all the texture images.

Physics

As of version 1.4, physics support was added to the COLLADA standard. The goal is to allow content creators to define various physical attributes in visual scenes. For example, one can define surface material properties such as friction. Furthermore, content creators can define the physical attributes for the objects in the scene. This is done by defining the rigid bodies that should be linked to the visual representations. More features include support for ragdolls, collision volumes, physical constraints between physical objects, and global physical properties such as gravitation.

Physics middleware products that support this standard include Bullet Physics Library, Open Dynamics Engine, PAL and NVIDIA's PhysX. These products support by reading the abstract found in the COLLADA file and transferring it into a form that the middleware can support and represent in a physical simulation. This also enables different middleware and tools to exchange physics data in a standardized manner.

The Physics Abstraction Layer provides support for COLLADA Physics to multiple physics engines that do not natively provide COLLADA support including JigLib, OpenTissue, Tokamak physics engine and True Axis. PAL also provides support for COLLADA to physics engines that also feature a native interface.

Versions

• 1.0: October 2004
• 1.2: February 2005
• 1.3: June 2005
• 1.4.0: January 2006; added features such as character skinning and morph targets, rigid body dynamics, support for OpenGL ES materials, and shader effects for multiple shading languages including the Cg programming language, GLSL, and HLSL. First release through Khronos.
• 1.4.1: July 2006; primarily a patch release.
• 1.5.0: August 2008; added kinematics and B-rep as well as some FX redesign and OpenGL ES support

See also

• FBX
• U3D
• X3D / VRML
• 3DMLW (3D Markup Language for Web)
• List of vector graphics markup languages
• List of computer standards

External links

• Official homepage
• COLLADA website
• OpenCOLLADA Project
• ColladaLoader
• GLC_Player