Save 3D Meshes in Custom Binary Format

Aspose.3D for Java API has support to open any supported 3D document, and then write meshes in the binary file.

Load 3D File and Write Meshes in Custom Binary Format Programming Sample

Accept method exposed by the RootNode member in the Scene class allows to visit each sub node. The code snippet below allows to convert meshes only.

// The path to the documents directory.
String MyDir = RunExamples.getDataDir();
// load a 3D file
Scene scene = new Scene(MyDir + "test.fbx");
/*
* 3D format demonstration is simple
*
* struct File {
*   MeshBlock blocks[];
* };
*
* struct Vertex {
*   float x;
*   float y;
*   float z;
* };
*
* struct Triangle {
*   int a;
*   int b;
*   int c;
* };
*
* struct MeshBlock {
*   int numControlPoints;
*   int numTriangles;
*   Vertex vertices[numControlPoints];
*   Triangle faces[numTriangles];
* };
*/
// open file for writing in binary mode
try (DataOutputStream writer = new DataOutputStream(new BufferedOutputStream(new FileOutputStream(MyDir + "Save3DMeshesInCustomBinaryFormat_out"))))
{
    // visit each descent nodes
    scene.getRootNode().accept(new NodeVisitor(){
        @Override
        public boolean call(Node node) {
            try {
                for (Entity entity : node.getEntities()) {
                // only convert meshes, lights/camera and other stuff will be ignored
                if (!(entity instanceof IMeshConvertible))
                    continue;
                Mesh m = ((IMeshConvertible) entity).toMesh();
                List<Vector4> controlPoints = m.getControlPoints();
                // triangulate the mesh, so triFaces will only store triangle indices
                int[][] triFaces = PolygonModifier.triangulate(controlPoints, m.getPolygons());
                // gets the global transform matrix
                Matrix4 transform = node.getGlobalTransform().getTransformMatrix();
                // write number of control points and triangle indices
                writer.writeInt(controlPoints.size());
                writer.writeInt(triFaces.length);
                // write control points
                for (int i = 0; i < controlPoints.size(); i++) {
                    // calculate the control points in world space and save them to file
                    Vector4 cp = Matrix4.mul(transform, controlPoints.get(i));
                    writer.writeFloat((float) cp.x);
                    writer.writeFloat((float) cp.y);
                    writer.writeFloat((float) cp.z);
                }
                // write triangle indices
                for (int i = 0; i < triFaces.length; i++) {
                    writer.writeInt(triFaces[i][0]);
                    writer.writeInt(triFaces[i][1]);
                    writer.writeInt(triFaces[i][2]);
                }
            }
        } catch(Exception e) {
            e.printStackTrace();
        }
        return true;
    }
});
}