@Override
    public void read(JmeImporter importer) throws IOException {
        InputCapsule capsule = importer.getCapsule(this);
        a = (Vector3f) capsule.readSavable("a", Vector3f.ZERO.clone());
        b = (Vector3f) capsule.readSavable("b", Vector3f.ZERO.clone());
        c = (Vector3f) capsule.readSavable("c", Vector3f.ZERO.clone());
    }
De-serialize this rectangle from the specified importer, for example
when loading from a J3O file.

@param importer (not null)
@throws IOException from the importer
jme3-core/src/main/java/com/jme3/math/Rectangle.java