Game Development Reference
In-Depth Information
using COLLADA content. As more and more applications pass the conformance
test, the end users are invited to check the published results to check the result of
a specific test that can help track down an issue. Everyone can help by requesting
his or her favorite application vendor to submit its COLLADA conformance test to
Khronos.
The first thing to do when encountering issues with a COLLADA export is to
make sure the correct, up-to-date exporter is used. In particular there are at least
three existing COLLADA importer/exporters for Autodesk 3dsMAX and Maya.
The basic one is provided by default by Autodesk and does internal conversion
between COLLADA and Autodesk proprietary FBX format, which has some limi-
tations; the FCollada [Feeling Software 11] plug-in, which has been used by many
developers successfully; and the core of implementations such as Adobe Photoshop.
However, FCollada is no longer maintained, and a new faster SAX style plug-in can
now be used, known as OpenCOLLADA [NetAllied Systems 09]. Installing a plug-
in for COLLADA import/export will require disabling the default FBX COLLADA
implementation, but that is definitely the first thing to do when having bugs, or
performance or memory issues with COLLADA with 3ds Max or Maya.
9.3 Schema Validation
When tracking down an issue with a COLLADA document, it is always dicult to
know if the issue is generated by the application that exported the document, or
by the application that is importing the content. The first thing to do is to make
sure the document is a valid COLLADA XML document. If an error is reported,
then we will know there is a problem application that has exported the document.
If this is the case, one should check if a better exporter is available, if a different set
of exporter options can be used, or if the content can be modified in the application
to avoid the feature causing an issue. In any case, if the document is invalid, the
error should be reported to the application vendor. The first test is to check if
the COLLADA document validates against the COLLADA schema. A COLLADA
document always contains a reference to the COLLADA namespace:
ure9.1
.
Thelinktotheschema
http://www.khronos.org/files/collada schema 1 4
is provided on this page and can be saved as
collada_schema_1_4.xsd
locally for
examinination or faster access.
There are many XML tools that can be used to validate a document against a
schema. The method we propose here is to write a simple C# program using the
free Express edition of Visual Studio [Microsoft 10]. The code below can easily be
extended to create other utilities to examine and manipulate COLLADA files.
