Supported Scene Elements and Attributes for COLLADA

 
 
 

| Geometry | Lights | Cameras | Hierarchies | Deformations | Animation | Constraints | Physics | Shading | User Data | File Referencing | Update Mechanism

The following tables list the features supported when importing into and exporting from Softimage using the COLLADA (*.dae) format.

NoteA complete description of the COLLADA file format can be found at http://www.collada.org.

Geometry

Element

Softimage Export vs. Softimage Import

Comments

Polygon Meshes

Yes

 

Triangles

Yes

Triangle strips are not supported.

Polygons

Yes

When exporting, Softimage uses the <polylist> element instead of the <polygons> element. Since Softimage does not export polygon holes, the <polylist> element is used for its more compact representation. However, the <polygons> element is supported on import.

Polygon Clusters

Yes, on export.

No, on import.

Subdivision and triangulation are not supported. If you export your geometry as subdivided (Apply Subdivision to Geometry option) or triangulated (Convert Geometry to Triangles option), then polygon clusters will not be exported.

Polygon Vertex Clusters

Yes, on export.

No, on import.

 

Polygon Edge Clusters

No

 

Splines

No

 

NURBS

No

 

Nulls

Yes

 

UVs

Yes

Prior to Crosswalk version 2.5, UV texture coordinates were output to the COLLADA file format as follows:

<accessor source="#geometries_0-channel1-array" count="24" stride="2">

<param name="U" type="float"/>

<param name="V" type="float"/>

</accessor>

Now, instead of "U" and "V", Crosswalk uses "S" and "T" for the parameter names as defined in the COLLADA specification.

<accessor source= "#geometries_0-channel1-array" count= "24" stride= "2">

<param name= "S" type= "float"/>

<param name= "T" type= "float"/>

</accessor>

Vertex Color

Yes

Also referred to as color at vertices (CAV) properties.

Normals

Yes

 

Texture Tangents

Yes

Tangents and binormals are stored in color at vertices (CAV) properties. Crosswalk identifies whether or not a CAV property contains tangent or binormal data as follows: Crosswalk looks for the TangentOp2 operator.

  • IIn Softimage 6.5 and earlier, if the operator is present, tangent data is assumed and exported (binormals were not directly supported). When exporting, binormals should be recomputed by the cross product of the normals and the texture tangents.

  • IIn Softimage 7.0 and later, if the operator is present, then Crosswalk reads the Operator Type flag which indicates whether tangents or binormals should be exported.

If Crosswalk does not find a TangentOp2 operator, then it looks for the sub-string tangent or binormal in the CAV property's name.

If you renamed the property and did not retain tangent or binormal as part of the name, the property will be exported as vertex colors only.

In COLLADA, tangents and binormals map to the "TEXTANGENT" and "TEXBINORMAL" semantics. Example:

<polylist count="6" material="Scene_Material">

...

<input semantic="TEXTANGENT" source="#geometries_0-Tangents" offset="2"/>

<input semantic="TEXBINORMAL" source="#geometries_0-Binormals" offset="3"/>

</polylist>

For more information, see Working with Tangent and Binormal Maps [Texturing].

Texture Binormals

Yes

 

Lights

Element

Softimage Export vs. Softimage Import

Comments

Ambient

Yes

Prior to Crosswalk 3.1, ambient lights were imported at the scene origin and converted to point lights.

Infinite

Yes

 

Point

Yes

 

Spot

Yes

 

Light Common Shading

Yes

When importing a light, its intensity is set to 1.0 if no XSI Extra is present.

Cameras

Element

Softimage Export vs. Softimage Import

Comments

Perspective Lookat

Yes

 

Perspective Rotation

Yes

 

Orthogonal

No

Orthographic cameras are not exported and they are converted to a perspective camera on import.

Extra Camera Data

Partial

 

Hierarchies

Element

Softimage Export vs. Softimage Import

Comments

SRT Node Transforms

Yes

 

Advanced SRT Node Transforms

Yes

Pivot, neutral pose, etc.

Instances (model)

Yes

 

Instances (primitive)

Partial

There is only one instance of each primitive in the hierarchy data.

Deformations

Element

Softimage Export vs. Softimage Import

Comments

Envelopes

Yes

Including bind pose matrices and envelope weights.

In addition, Crosswalk adds type="JOINT" on all nodes (envelope deformers) that are a part of a skeleton's hierarchy. This is done to support applications that rely on the type="JOINT" description to import envelopes/skins properly. This applies only to the export of envelope deformers from Crosswalk.

Shapes

Partial

  • Support for shape sources (Shape Keys).

  • Shape source names are preserved.

  • No weight animation supported.

Bones

No

Converted to nulls.

Animation

Element

Softimage Export vs. Softimage Import

Comments

Fcurves (constant)

Yes

 

Fcurves (linear)

Yes

 

Fcurves (spline)

Yes

 

Fcurves (hermite)

Yes

 

Fcurves (per key interpolation)

No

 

Constraints

Element

Softimage Export vs. Softimage Import

Comments

Constraints

No

Plotted on export using Animation Resampling options.

IK

No

Plotted to FK.

Physics

Element

Softimage Export vs. Softimage Import

Comments

Rigid Body Dynamics

No

 

Shading

Element

Softimage Export vs. Softimage Import

Comments

Common Shading

Yes

The common profile is fully supported. The exporter analyzes the material render tree and guesstimates the best approximation to convert from a full-fledged shader node network to the common profile. The ProgID of the first shader attached to the surface port of the material is the one that drives the common profile description. For example, if the first shader attached to the material's surface port has a ProgID that is "softimage.phong.1", then the exporter will generate a <phong> element within the effect description. Textures attached to the emission, diffuse, specular, and ambient ports are also exported and imported correctly.

Support for alpha-driven transparency with a texture is handled as follows:

  • When exporting "Use Alpha" with a texture the "Scale" is not taken into account.

  • When exporting "Use Alpha" with a color, the "Scale" is baked into the color.

  • When importing in the A_ONE mode with a texture, the COLLADA "Transparency" is ignored and the "Scale" is set to 1.0.

  • When importing in the A_ONE mode with a color, the COLLADA "Transparency" is baked into the color and the "Scale" is set to 1.0.

DirectX

No

 

Cg Profile Effects

Yes

CG profile is supported in two flavors: The first flavor uses the NV_import extra which references an external CGFX file. This is used when the CGFX shader node attached to the material is using an external reference to a CGFX file.

The output looks like this:

<effect id="check3d_fx">

<extra type="import">

<technique profile="NV_import">

<import profile="cgfx" url="file://\lobby\dev\CGFX\check3d.cgfx" />

</technique>

</extra>

</effect>

The second flavor uses the full COLLADA FX specification for the CG profile. The effect description needs to be set within the CGFX node in order to work.

User Data

Element

Softimage Export vs. Softimage Import

Comments

Custom Psets

Yes

 

User Data Blob

No

 

Foreign Extras

Yes

The foreign extra element does not use the Softimage technique profile. These extras are imported and persisted as opaque user data blobs in the Softimage scene. They are restored on export.

File Referencing

Element

Softimage Export vs. Softimage Import

Comments

Model Files

No

 

Images

Yes

On export, you can select the Keep Referenced Paths Relative checkbox (default), otherwise paths are resolved to absolute paths.

On import, any referenced paths within the Crosswalk file are automatically resolved to absolute paths.

Shaders

Yes

 

FX and CGFX Files

Yes

On export, you can select the Keep Referenced Paths Relative checkbox (default), otherwise paths are resolved to absolute paths.

On import, any referenced paths within the Crosswalk file are automatically resolved to absolute paths.

COLLADA Files

No

Softimage only supports external references to images and CGFX files. References to COLLADA files are not supported — resolve them within the same document instead.

Update Mechanism

Element

Softimage Export vs. Softimage Import

Comments

Update

No

 

Creative Commons License Except where otherwise noted, this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License