Is there a simple way to convert .dae files to .obj format.
You can use basically any currently available 3D modeling software to convert .dae to .obj format (3D Digital Asset Exchange File to a Wavefront 3D Object File). Certain CAD/3D modeling conversion utilities are capable of such a conversions, too.
Most commonly, a .dae to .obj conversion is attempted in order to create a generic .obj version of your Collada format (.dae).