The plant model showed a plant with several thin pipes, heavy tanks, and tall structures. The original model started out as several surfaces and solids that were not all connected, and had several gaps. To make the model printable, all the thin elements needed to be thickened, the tall structure needed to be trimmed down to fit in the printer, and gaps between pipe connections needed to be filled.
The picture below shows the original model.
A) Heavy, solid elements need to be hollowed out to reduce their weight so that they will not break the support structures beneath them. This can easily be done using the Subtract Solids and Shell Solid tools.
B) Thin pipes or rails in models need to be thickened and made solid before printing. The Offset Surface tool works very well for thickening the pipes, and the Convert to Solid tool closes the open ends to create a solid element.
C) Using Offset Surface on joints in pipes can cause self-intersection problems. If this occured, the profile of the pipe could be extruded along a path to recreate the joint.
D) There are often gaps between the pipes at the gasket connections. These could easily be fixed by extruding the profile of the pipe through the gap using the Surface by Extrusion tool.
E) I-beams within the model can be extrememly thin, and will not support the the pipes and other elements. These needed to be replaced with thicker slab solid beams to be more stable.
F) Small elements in the model need to either be thickened or removed from the model. The Offset Surface and Modify Solid tools were helpful for thickening the small elements.
The picture below shows the printed plant model.