Re-build / clean-up a mesh from scratch for 3D printing

[guache]

I use Houdini to design parts for 3D printing. The requirement for 3D printing is manifold geometry ("watertight" models, no single edges, no "T" connections between polys etc). I have a polygonal object, the result of many Boolean operations. From my, human view, it looks "watertight": it's a polygonal shell that encloses a definite region in space, with no holes. But my slicing software (Simplify3D) gives me "non-manifold" verdict, high-lighting in red many of the Boolean'd edges. Is there some way in Houdini (SOP or OTL) to cleanly rebuild a mesh from scratch (based on an existing mesh) and clean it up for 3D printing? For example, turn it into a point cloud, then I, as a human, could provide the software with clues where "inside" and "outside" is (e.g. by creating points and defining them as "inside" and "outside" the model. The SOP or OTL would then rebuild all polys in a way that creates a consistent, clean mesh. I tried the PolyDoctor SOP and turned most of its "Repair" options on, but it didn't do anything useful.

Edited March 1, 2019 by guache

[kleer001]

I've done this before, printing things from Houdini. It's a pain.

 

Maybe try a high resolution VDB from polygons and then back into polygons. Or you can use a cleaner process than polygonal boolianing. Try working in VDBs, using the VDB combine Operation of SDF Union/Intersection/Difference and only outputting polygons when you're done.

Working in VDBs will garuntee that you're nominally water tight, most of the time. But the geometry won't be as clean as it can be. In the end what you really want to do is build your geometry 'correctly' from the start or retopologize once you have a shape you like (which is a whole nuther discipline).

Edited March 1, 2019 by kleer001