Some young people may be enchanted by the music, fashion and ideas of the 70's. Few of them, however, have heard about the Newell's teapot, a hit in the Computer Graphics community. Created in 1975 by a researcher of the University of Utah - Martin Newell - , the teapot model was a star of many bench tests of new realistic graphic algorithms and techniques. You will find a historical appraisal of its pedigree in an entry of Wikipedia: "Utah Teapot". The Utah teapot dataset spread around the world beyond the following decade and may be found yet here and then. It contains the control points of 28 degree 3 Bezier patches that defines the outer surface of the main teapot body, its lid, its spout and its handle. It is not a solid however. It misses the interior surfaces of the main body and the spout, has no bottom closure, and the handle doesn't meet the body nicely. I have been working in a modelling system that allows the use of Bezier surfaces as boundary of OpenSCAD models. It is now under tests and I thought that the Utah Teapot would be a nice demo of the system. I have completed the teapot model correcting some imperfections in the handle and creating a internal surface where it is needed. And I got this outcome. <http://forum.openscad.org/file/n17166/OpenSCAD_Teapot.png> This is a render of the model and it has passed all CGAL checks so it can be boolean-operated with other solids. Here is a difference operation that shows the internal surfaces of the model: <http://forum.openscad.org/file/n17166/OpenSCAD_cut_Teapot.png> How this model was built? Well, it is the boolean operation of 3 polyhedron (the spout, the handle and a solid to make the spout hole in the main body) and two rotate_extrude of Bezier curves (the main body and the lid). I could avoid the use of rotate_extrude but I have prefered that way to illustrate many modelling alternatives. To model the main body, I extracted the control points of a profile (section) of the main body from the dataset, and used that to feed rotate_extrude. The lid has been made the same way. For the spout and the handle, I have used the dataset patches, added patches for the spout inner surface and close their ends with planar faces. <http://forum.openscad.org/file/n17166/OpenSCAD_disassembled_Teapot.png> For each independent part (spout and handle), I collect all the surface information (vertices of planar faces and meshes of Bezier surfaces) and send all to a module which builds the data for a polyhedron primitive. That module scan the data, builds the vertex lists and the triangular face lists without caring to identify the common vertices of adjacent patches or adjacent to a face and a patch. So the vertex list sent to the polyhedron has many repetitions. CGAL cares to consolidate the vertex list and builds a solid when the union of all surfaces is a manyfold. My lifemate was kind to 3D print the teapot from a stl file I generated with OpenSCAD. A very tiny teapot: with a diameter of only 1 inch. <http://forum.openscad.org/file/n17166/Without_lid_1-1024.jpg> I was amazingly surprised that a so small version of the teapot is able to pour water from the spout! <http://forum.openscad.org/file/n17166/Pouring_water-1024.jpg> Pourring water-1024.jpg -- View this message in context: http://forum.openscad.org/A-70-s-revival-the-Utah-Teapot-tp17166.html Sent from the OpenSCAD mailing list archive at Nabble.com.

Really nice to see a physical instantiation of the Utah teapot. Thanks. Looking fwd to seeing whatever it is you're doing :) -- View this message in context: http://forum.openscad.org/A-70-s-revival-the-Utah-Teapot-tp17166p17167.html Sent from the OpenSCAD mailing list archive at Nabble.com.

         - Michele

On 04-22-2016 7:48 PM, Ronaldo wrote: > Some young people may be enchanted by the music, fashion and ideas of the > 70's. Few of them, however, have heard about the Newell's teapot, a hit in > the Computer Graphics community. > Yes indeed. The Teapot was all the rage at SIGGRAPH for a while in the 80's. IIRC, it made the cover of the Proceedings one year. Thanks for the trip down memory lane. I'll have to print this one out for sure. - Michele

        - Michele

There’s a decent .stl file floating around (thingiverse?) I downloaded it and printed a full-size model a few years ago. I don’t think I want tea brewed in an ABS pot, but it appears functional. Which, of course, means that the .stl model is wrong. The original model didn’t have a bottom. And then there’s the whole “aspect ratio” thing… Google is your friend. If you can’t find Google, find an old guy who was there in the beginning. I’m a newbie. I didn’t make it to the first SIGGRAPH. My first one was 1976, I think… -- Kenneth Sloan KennethRSloan@gmail.com Vision is the art of seeing what is invisible to others. > On Apr 23, 2016, at 19:17 , Michele Denber <denber@mindspring.com> wrote: > > On 04-22-2016 7:48 PM, Ronaldo wrote: >> Some young people may be enchanted by the music, fashion and ideas of the >> 70's. Few of them, however, have heard about the Newell's teapot, a hit in >> the Computer Graphics community. >> > > Yes indeed. The Teapot was all the rage at SIGGRAPH for a while in the 80's. IIRC, it made the cover of the Proceedings one year. Thanks for the trip down memory lane. I'll have to print this one out for sure. > > - Michele > > > > _______________________________________________ > OpenSCAD mailing list > Discuss@lists.openscad.org > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org

Michele wrote > I'll have to print this one out for sure. Well, you will need a stl file for that: teapot_demo.stl <http://forum.openscad.org/file/n17183/teapot_demo.stl> As I remarked and Sloan confirmed, the original Newell's teapot is a rather incomplete model. Here you may have an idea of the original model: <http://forum.openscad.org/file/n17183/OpenSCAD_original_cut_Teapot.png> I will publish my Bezier libraries and modelling system as soon as it has been enough tested. By now, for give you a glimpse of how it is used, you may take a look into the OpenSCAd file I used to render the teapot. It is a rather complete and complex demo though. teapot_demo.scad <http://forum.openscad.org/file/n17183/teapot_demo.scad> -- View this message in context: http://forum.openscad.org/A-70-s-revival-the-Utah-Teapot-tp17166p17183.html Sent from the OpenSCAD mailing list archive at Nabble.com.

         - Michele

On 04-24-2016 11:01 AM, Ronaldo wrote: > Well, you will need a stl file for that: > teapot_demo.stl<http://forum.openscad.org/file/n17183/teapot_demo.stl> > Thanks, and for the source code too! That worked out very nicely without even needing support. 1987 was a big year for the Teapot at SIGGRAPH. It was featured in no fewer than three papers. - Michele