In recent years, Trimble has tightened this program. You used to get a 12-month Pro license; now, the free desktop version for students is sometimes restricted to "SketchUp for Schools" (which runs in a browser). Always check current terms, but as of this writing, secondary and university students can still get SketchUp Studio free for one year.
When a user installs a legitimate copy of SketchUp Pro, the software communicates with Trimble’s (the parent company) servers. It sends a digital "handshake"—a unique identifier generated from your license key. If the server recognizes the key, it sends back a "token" that unlocks the full suite of features, such as Layout, Style Builder, and advanced import/export capabilities.
: Full access to the desktop version, including LayOut and Style Builder. Duration : 7 days.
While there is no permanent, completely free version of SketchUp Pro