I have several OpenSCAD models that I created as seperate parts from blueprints. The parts nest together, and the assembled real objects have several hollow volumes. I would like to make the overall OpenSCAD model solid. (So that I can difference a uniform cylinder out of the middle.) The shape of the model does not seem like the hull() function would work well. One of the models is made form 5 parts, another is made from 2 parts. Pictures:

Your models looks great, but your question is not very clear On Wed, 9 Apr, 2025, 3:42 am leebc via Discuss, <discuss@lists.openscad.org> wrote: > I have several OpenSCAD models that I created as seperate parts from > blueprints. > > The parts nest together, and the assembled real objects have several > hollow volumes. > > I would like to make the overall OpenSCAD model solid. (So that I can > difference a uniform cylinder out of the middle.) > > > The shape of the model does not seem like the hull() function would work > well. > > One of the models is made form 5 parts, another is made from 2 parts. > > Pictures: > _______________________________________________ > OpenSCAD mailing list > To unsubscribe send an email to discuss-leave@lists.openscad.org >

It isn't quite clear which hollow parts you want to fill. Maybe copy-paste those images into your favorite paint program, and add circles and arrows. I agree that hull will not do the trick, because it will not leave any concavities. It looks like dropping in one or more appropriately-sized and appropriately-positioned cylinders will probably do the trick. But if you have the original OpenSCAD models... why not modify them?  Presumably they difference away the various hollow parts; make them (optionally?) not do that.

The approach I typically use is to add (by union or implicit union) filler shapes (cylinders, hollow cylinders, non-uniformly-scaled spheres, rotate-extruded polygons, etc) that overlap (by epsilon larger in all directions) the hollow voids that I want filled. If you don't have the actual dimensions, it can be done visually, sometimes painstakingly by trial and error, with panning and zooming. It shouldn't be too hard for you to position and size the fillers since you're obviously having luck generating and viewing cross sections. Regards, Curt On 4/8/2025 3:11 PM, leebc via Discuss wrote: > > I have several OpenSCAD models that I created as seperate parts from > blueprints. > > The parts nest together, and the assembled real objects have several > hollow volumes. > > I would like to make the overall OpenSCAD model solid. (So that I can > difference a uniform cylinder out of the middle.) >

The parts are interesting, actually I find them fascinating and have to ask what they are for... I remember machining a part for some commercial gas heaters that look a lot like the part with small rings around the edge, but my guess is they are more for something like mixing air/liquid to help with laminar flow, but I could be wrong... Anyway, back to your question. Like Curt, I would suggest making each parts with the pieces you are interested in being parametric and write it with basic shapes coupled with unions and differences. EBo -- On Wed, Apr 9, 2025 at 1:22 AM Curt McDowell via Discuss < discuss@lists.openscad.org> wrote: > The approach I typically use is to add (by union or implicit union) > filler shapes (cylinders, hollow cylinders, non-uniformly-scaled > spheres, rotate-extruded polygons, etc) that overlap (by epsilon larger > in all directions) the hollow voids that I want filled. If you don't > have the actual dimensions, it can be done visually, sometimes > painstakingly by trial and error, with panning and zooming. It shouldn't > be too hard for you to position and size the fillers since you're > obviously having luck generating and viewing cross sections. > > Regards, > Curt > > On 4/8/2025 3:11 PM, leebc via Discuss wrote: > > > > I have several OpenSCAD models that I created as seperate parts from > > blueprints. > > > > The parts nest together, and the assembled real objects have several > > hollow volumes. > > > > I would like to make the overall OpenSCAD model solid. (So that I can > > difference a uniform cylinder out of the middle.) > > > _______________________________________________ > OpenSCAD mailing list > To unsubscribe send an email to discuss-leave@lists.openscad.org >

Can you not enclose the models in a union statement and the diff the void from that? On Wed, Apr 9, 2025, 05:12 leebc via Discuss <discuss@lists.openscad.org> wrote: > I have several OpenSCAD models that I created as seperate parts from > blueprints. > > The parts nest together, and the assembled real objects have several > hollow volumes. > > I would like to make the overall OpenSCAD model solid. (So that I can > difference a uniform cylinder out of the middle.) > > > The shape of the model does not seem like the hull() function would work > well. > > One of the models is made form 5 parts, another is made from 2 parts. > > Pictures: > _______________________________________________ > OpenSCAD mailing list > To unsubscribe send an email to discuss-leave@lists.openscad.org >