A coffered ceiling for a San Marino home underway

Coffered ceiling going from sketchup to reality. Today I layed out and then taped the centerlines for the foundation. 

The ceiling is 13 feet high and the space is narrow so an irregular grid will be best. I chose to use 1x4 for the foundation for box beams that will be coming next. 

Here's the plan coming next...

Visualization of coffered ceiling