COLLADA exporter
The dev branch tp/TKCOLLADA hosts an experimental COLLADA exporter: "COLLADA is a royalty-free XML schema that enables digital asset exchange within the interactive 3D industry".
The COLLADA exporter just works as the STL exporter. Here is an example that creates a sphere and exports the result to a DAE file:
BRepPrimAPI_MakeSphere my_sphere(50.); my_sphere.Build(); ColladaAPI_Writer myColladaWriter; myColladaWriter.Write(my_sphere.Shape(), "sphere.dae");
You can pass any TopoDS_Shape to the COLLADA exporter. This TopoDS_Shape can come for instance from a standard file (STEP, IGES) or any .brep OCC file. A test was conducted with a part named "cylinder_head", avaible from the OpenCascade.org website (see http://www.opencascade.org/showroom/shapegallery/gal4/).
In the following example, the .brep file is loaded as a TopoDS_Shape and passed to the COLLADA exporter. This generates a file named "15_cylinder_head.dae" which can be imported into Google Sketchup or viewed the the builtin OSX viewer (see screenshots below).
The code for this example is the following:
// import file Standard_CString aFileName = (Standard_CString) "15_cylinder_head.brep"; BRep_Builder aBuilder; TopoDS_Shape aShape; Standard_Boolean result = BRepTools::Read(aShape,aFileName,aBuilder); // export TopoDS to a DAE file ColladaAPI_Writer myColladaWriter; myColladaWriter.Write(aShape, "15_cylinder_head.dae"); }
So far, the COLLADA exporter only exports a triangular mesh with normals for a single shape. The exporter comes as a new OCE Toolkit, named TKCOLLADA, that was obtained from a copy/paste of the TKSTL toolkit before being modified. The developments are currently in an experimental phase: the code is in a very early stage, docstrings from the STL toolkit ware not modified, the C++ code still need optimization as well as refactoring maybe. These first experiments aim at studying the feasibility of such an impoter/exporter.
The first experiments show that:
- computing time might be high for some complexe geometries (a few minutes for the cylinder head),
- the generated DAE file (XML formatted) is quite big: the mesh has to be reduced in order to embed a lightweight tesselation into the XML representation.
- Use LDOM to handle XML elements
- Add support for multiple shapes (TopoDS_Compound)
- Update the CDL files
- Enable passing an AIS_Shape
- Add support for KMZ export