plugin for SketchUp is a specialized professional engineering toolset designed for MEP (Mechanical, Electrical, and Plumbing) design and 3D steel structures. While the plugin itself is a premium paid product, users can access its full features for free during a limited evaluation period. Availability of "Free" Versions

If you absolutely cannot afford the 3skeng subscription, you are not out of luck. Several native tools and free plugins can mimic some functionality of 3skeng.

The plugin is divided into specific engineering modules. During your free trial, you have access to all of them.