PlanGrid’s interactive blueprint app lets project teams view, share, annotate, and sync blueprints on an iPad and in the cloud. By maintaining one master set on the web, it’s possible to make annotations or take progress photos on the fly and keep your team updated via email.  Projects cache locally on your device, so you’ll always have access to your drawings. It’s also the only software that digitally leafs in your new drawing sheets, so you can review your old versions at any time, the company says.  It’s fast, too, rendering drawings quickly while allowing you to swipe and scale with the touch of your finger.