For reference information about the Crosswalk SDK, see the Crosswalk SDK Reference. For more information about how to use the Crosswalk SDK to read and write COLLADA files, see Workflow for Accessing COLLADA Data..
COLLADA is an XML-based digital asset exchange (*.dae) schema designed to transport data between 3D content creation tools. A more complete definition can be found on the COLLADA web site. COLLADA is primarily targeted for the exchange of assets in a game pipeline, but it can be used in any area of 3D content creation that requires an intermediate format and good tool interoperability.
Since the release of Softimage v5.1, COLLADA has been officially endorsed and adopted as an important supported file format. Softimage has also joined the Khronos group to help promote and evolve the COLLADA specification. Previous integrations of COLLADA in Softimage were done via an external plug-in which can still be found on the COLLADA web site.
The COLLADA converter is integrated inside the Crosswalk SDK, so any applications implemented using the Crosswalk SDK can import and export COLLADA files. The IO Layer (the low-level parser) is based on XercesC and works in SAX mode to reduce the memory footprint when importing COLLADA files. Data is stored in a template managed via the CCOLLADATemplate class (a specialization of the CdotXSITemplate class). The Semantic Layer (the high-level classes) include classes that are specifically designed to support COLLADA elements (for example, CSLCOLLADAScene, CSLCOLLADAMesh, CSLCOLLADAActionFCurve, etc).
|
For reference information about the Crosswalk SDK, see the Crosswalk SDK Reference. For more information about how to use the Crosswalk SDK to read and write COLLADA files, see Workflow for Accessing COLLADA Data.. |
The following scenarios represent the ways in which you would typically use COLLADA with Softimage:
|
Scenario |
Description |
|
Softimage and the Game Pipeline |
The COLLADA exporter allows the game developer to take content created in Softimage and export it in a COLLADA file that can then be used and processed in a game pipeline. The basic elements primarily are supported, such as hierarchies, geometries, material and effect assignments, skinning, and transformation animation. In the area of effects, support for the Sony PS3 environment is enhanced by the integration of the CG profile of the COLLADA FX specification in Softimage shader nodes and in the COLLADA converters. |
|
Migrating Existing dotXSI Game Pipelines to COLLADA |
The integration of COLLADA in the Crosswalk SDK provides current users of the dotXSI file format a smooth transition to COLLADA. By subclassing the existing dotXSI classes and reusing the same libraries and the same import/export tools the transition to COLLADA is essentially transparent when using Softimage. As a result, tools that currently compile with the Crosswalk SDK only require very small updates to use COLLADA as the file format. |
|
Softimage and Interoperability with Other Digital Content Creation Tools |
The COLLADA exporter and importer in Softimage allow you to exchange 3D data with any digital content creation tool that supports the following versions of COLLADA: • On import, both COLLADA 1.4.0 and 1.4.1 are supported. • On export, only COLLADA 1.4.1 is supported. |
See Importing and Exporting dotXSI Files for details on how to set up options for importing from and exporting to COLLADA files using the Softimage user interface. For a list of supported COLLADA features in Softimage and how they map over, see Supported Scene Elements and Attributes for dotXSI.
Extras
COLLADA uses a special XML element named extra to store information that is not used in a specific 3d content creation package. For Softimage, there are two types of extra elements that are supported by the COLLADA converters:
• When Softimage-specific information is exported to a COLLADA file, it is written to extra elements under the XSI technique profile.
• User data that originated outside of Softimage is stored in extra elements under a foreign profile (that is, the XSI technique profile is not used). When these data are imported into Softimage, they are persisted as opaque user data blobs in the Softimage scene and are restored on export.
Example: Softimage data exported to COLLADA extra element
In this example, a scene node has the full Softimage transformation data as well as visibility flags and global material assignment data in the Softimage extra:
<extra>
<technique profile="XSI">
<SI_Visibility>TRUE</SI_Visibility>
<XSI_Transform>
0.000000 0.000000 0.000000 0.000000 0.000000 0.000000 XYZ 1.000000 1.000000 1.000000 TRUE 0.000000 0.000000 0.000000
0.000000 0.000000 0.000000 0.000000 0.000000 0.000000 1.000000 1.000000 1.000000 0.000000 0.000000 0.000000 0.000000
0.000000 0.000000 1.000000 1.000000 1.000000 0.000000 0.000000 0.000000 0.000000 0.000000 0.000000 1.000000 1.000000
1.000000 0.000000 0.000000 0.000000
<XSI_Limit>"posx" FALSE 0.000000 FALSE 0.000000</XSI_Limit>
<XSI_Limit>"posy" FALSE 0.000000 FALSE 0.000000</XSI_Limit>
<XSI_Limit>"posz" FALSE 0.000000 FALSE 0.000000</XSI_Limit>
<XSI_Limit>"rotx" FALSE 0.000000 FALSE 0.000000</XSI_Limit>
<XSI_Limit>"roty" FALSE 0.000000 FALSE 0.000000</XSI_Limit>
<XSI_Limit>"rotz" FALSE 0.000000 FALSE 0.000000</XSI_Limit>
</XSI_Transform>
<SI_GlobalMaterial>"check3d" "NODE"</SI_GlobalMaterial>
</technique>
</extra>
External Referencing
COLLADA supports external references to other COLLADA files, as well as image files and CGFX files. However, Softimage only supports external references to images and CGFX files. Other references must be resolved within the same document.
Autodesk Crosswalk v5.0