For advanced users, Curic DIO2 allows parametric stretching of components. It is a general modeling tool, not MEP-specific, but creative users have built piping libraries with it.
While not a replacement for 3skeng, Solid Inspector helps you fix solid groups. If you manually model pipes, this free tool ensures they are watertight for 3D printing or STL export. 3skeng plugin sketchup free
The free tier usually retains the ability to import IFC files (Industry Foundation Classes). If you are coordinating with an engineer using Revit or ArchiCAD, you can use 3skeng Free to bring that data into SketchUp and convert it into native 3skeng objects for viewing. For advanced users, Curic DIO2 allows parametric stretching
Used for structural steel modeling.
The short answer is no. The full-featured, commercial 3skeng plugin is not free. If you manually model pipes, this free tool
3skeng is developed by a Swiss company (3skeng GmbH) and operates on a paid subscription model. However, this does not mean the story ends here. There are three scenarios often confused with "free" access: