No Collide Tool
How to Use
The No Collide tool lets you make props non-solid, meaning you (and other players) can walk straight through them. This is very handy while building, as it lets you line up and pass through props without getting stuck.
To use it, hold Q and select the No Collide tool. Right click a prop to no-collide it, and right click to turn its collision back on.
Note: No-collided props are only allowed during the building phase, and you must have a Building sign up. Once you're finished building and the sign is down, your props must be collidable - leaving them no-collided outside of building is against the rules.