Efficient technique for modelling tubes and pipes is very useful for modelling engines, which are usually covered in the things head to toe.
The most straightforward method to creating tubes is to create a curve, and enabling the relevant geometry profile. Due to its imprecise nature, though, it is less ideal for creating rigid piping with straight runs and clean elbows; refer to the bevel/geometry node technique below.
In the object data properties panel for a curve object, expand geometry to reveal the bevel options, and set depth to adjust the thickness of the resulting geometry. The default resolution is quite high, so consider lowering it to save on polycount—1 results in a six-sided profile, 2 gives eight sides, and so forth.
At the top of the panel, use Resolution Preview U to adjust the resolution of the curve path. Something like 6 is usually good enough for most tubing.
Remember that the curves creation menu also has some presets for circles and arcs, which are good for heat exchangers, turbines, pumps, and the like.
As mentioned before, the trouble with the bezier curve technique is that it can be quite imprecise in creating clean, solid piping. Courtesy of KSP modder Zorg, however, One can use a combination of the bevel modifier and geometry nodes to achieve this effect. Effectively, it is a custom implementation of the skin modifier, generating a 3D pipe profile from a series of verticies and edges.
Courtesy of Zorg
Courtesy of Zorg
Begin with a single vertex and extrude it along the path of the desired pipe mesh. Once done, create a bevel modifier, set to verticies, and adjust the bevel amount and segments to something more reasonable.
Underneath the bevel modifier, add a geometry nodes modifier, and apply the following node structure to the modifier:
Convert the mesh to curve, then back to a mesh with a curve to mesh node, with the profile curve being fed with a curve circle node. The curve circle node can be set to your desired pipe resolution and radius. Finally, the generated mesh should be put through a set material node, applying the appropriate material for preview purposes, and then finally to the final output.
The result is an efficient modelling technique with straight piping runs and clean bends. The underlying verticies can be edited to modify the pipe non-destructively; just remember to apply all the modifiers when you are ready to UV unwrap and texture.
Like materials, you can enable fake user for the “pipe maker” geometry nodes, ensuring it is preserved for easy re-use for multiple pipes.
Below is a Blender file with a custom pipe maker node setup that you can use when modelling. It’s set up so that you can quickly adjust parameters in the right-hand properties menu—no fiddling with the geometry nodes setup if you don’t want to.