Introduction: Library of Congress Ornament
For my entry for the 3D Printed Ornament Design Challenge, I decided I wanted to do something inspired by one of our family’s favorite DC destinations-- the Reading Room in the Library of Congress' Jefferson Building. The beauty of the building and knowledge within is a great testament to the best of mankind and all the accomplishments yet to come!
Reading Room image is by Carol M. Highsmith and in the Public Domain
Step 1: Prep and Planning
I worked in Blender, which can be downloaded for free. It can be intimidating at first, but I've found tutorials are plentiful!
I typically work using Blender Units as Centimeters. Per the contest rules, the ornament could only be 3” by 3” which meant 7.6 centimeters by 7.6 centimeters.
I don't own a 3D printer, so I typically use companies like Shapeways to do my prints. Shapeways has start of the art 3D printers and can print in a variety of materials, including premium metals like gold and silver. I reviewed the Materials design requirements and decided that I would want my ornament to be 1 millimeter thick—which would keep it printable in the materials I was eyeing-- Strong & Flexible Plastic, Brass, and Premium Silver.
Deciding your materials and knowing their limitations from the get-go is really helpful and makes the process go MUCH smoother.
Step 2: Modeling the Base Ornament
Now the Jefferson room has eight arches, so I started offwith three planes (one on the Z axis, one on the Y axis, and one rotated 45 degrees on the Z access) to help me visualize my working area. I modeled just 1/16th of the ornament and used mirrors to fill in the rest.
I started by going to Add->Mesh->UV Sphere
I made it 7 centimeters by 7 centimeters by 7 centimeters.
I hit the Duplicate Objects button to make a second sphere. This one I wanted to make smaller as it was going to be the inside walls of my sphere. I mentioned I wanted my ornament to be 1mm thick, so my inside sphere is 2 mm smaller in diameter than my larger one.
I selected my smaller sphere and switched to Edit mode. I selected all the Faces and then I flipped the face normal by going Mesh->Normals->Flip Normals. This tells the smaller sphere that it is going to be on the inside.
To make my outside sphere pretty, I clicked on the Modifiers icon. I selected Add Modifier and added (and applied) a Subdivision Surface modifier to it.
I highlighted both my outer and my inner spheres and went to Object->Join to make them one single object. Now I had a single, hollowed out sphere.
Now, I only needed 1/16th of my sphere to model. So I needed to delete the parts of the sphere I didn't need.
You can do the Select->Border Select (as Jonathan Williamson demonstrates in How to Model a Pumpkin in Blender). However, at this point, I had lots and lots of faces and vertices because of the Subdivision Surface Modifier. So what I did was add cubes, size them, and rotate them to cover the parts of the sphere I didn’t want. Then I used the Boolean Modifier to subtract those cubes from my sphere.
Step 3: Modeling Windows and Doorways
Then I made a bunch of little objects for my windows and doors. They all started out as Add->Mesh->Cylinders of various sizes and rotations. For the doors, I took a cylinder and went into edit mode and dragged some of the vertices down. Then I used the Boolean Modifier to chop off the bottom.
I lined up my objects on my sphere. The planes really helped with visualization the layout. I also turned on all my Mirror Modifiers (More on that below) to see how everything looked as I work. As necessary, I rotated the objects so they were positioned better on the sphere.
Step 4: Carving the Windows and Doors
Tip - before carving, I usually make a backup of my work so far—be it through duplicate objects in the same file—or--- saving another file altogether. I have found if I have any issues with thin walls, it is often easier to fix in this stage rather than correct after all the mirroring and subtracting.
I used the Boolean Modifier to subtract all our little details from the spheres. (Again I have all my Mirror Modifiers on to see progress as I work).
After carving everything, I highlighted my sphere, went to my Print3D options in my left pane (via the free 3D Printing Toolbar Extension for Blender) and clicked on Solid to check to make sure my object is airtight.
I breathed a huge sigh of relief when I see there are 0 Non-Manifold edges. :)
Step 5: Mirroring My Ornament
I’ve modeled 1/16th of my ornament. Now I needed to mirror it around. First, I mirrored it over my Plane that is rotated 45 degrees along the Z access.
Then I mirrored it over X axis.
Then mirrored that over the Y.
Finally over Z.
After each mirror, I did another Solid check on the Print3D extensions to confirm I didn’t introduce Non-Manifold edges.
(If you do get Non-Manifold edges, Ctrl-Z to undo, and try redoing the mirror, this time unchecking the Merge option when you mirror)
Step 6: Modeling the Floor and Chairs
Inside my ornament, I have a small cylinder in the middle to serve as my Reading Room floor and I wanted to add some subtle detail reminiscent of chairs and aisles. For the chairs I did Add->Mesh ->Circle of various sizes.
I switched to Edit Mode, used Select->Border Select to select the vertices of the rings and did Mesh->Faces->Fill to make faces in my circles.
On the left pane, I picked Extrude Region to raise it up my circles up.
I used some sized and rotated cubes and the Boolean Modifier to carve out my aisles.
Once I had everything modeled, I moved it into place inside my sphere.
The reference image of the Reading Room Seats is by Jiuguang Wang and is licensed Creative Commons.
Step 7: Modeling My Ornament Hook
The ornament hook was really easy. I just went to Mesh->Add->Torus, sized it, rotated it, and placed it at the top of my Sphere.
Step 8: Finalizing Object and Preparing for Upload
Now that everything is in place, I selected my sphere, my floors, my chairs, and the torus and did an Object->Join to make them all into one object. I did my Print3D Solid check one more time.
As I was designing I was using centimeters as my Blender units. When I upload to a company for printing, they often use millimeters, so I sized my Dimensions up by 10.
Finally, I went to File->Export and saved my file to .STL which I uploaded for printing.
The final .STL file is attached. Don't have a printer? You can also print a copy at the ornament at Shapeways.