Preparing a Design for Layered Manufacturing

Final Rendered Bell Shape

In this assignment, we turned our geometrical representations into STL/SML files to use with a FDM machine.

When I first made the shape, I made a few overlapping b-splines with varying sweep shapes and dimensions. There were two sets of b-splines that alternated with each other, and I instantiated them, rotated around the z axis, to achieve a fully rounded shape.

However, I realized that it would be a bit confusing for a FDM to process many overlapping/intersecting shapes. I then recreated the shape by using my two b-splines, and instead of using a 3d cross section and creating many of them, I defined each b-spline as a cross section, and created a order 4 circular b-spline that would give me rotational symmetry (I used an order 4 b-spline because an order 3 b-spline had issues lining up the jagged bottom). Instead of using a normal sweep, I varied the last few control points of my original sweep to create a second sweep. This sweepmorph was extruded with a thickness to create a 3D shape. SLIDE's sweepmorph type allowed me to interpolate between the two splines, creating the jagged bottom of the bell.

When adding on the extra shapes, such as the ring on the head, or the eyes, I used simple SLIDE primitives (torus and sphere, respectively). For the eyes, I created a primitive thin half-sphere, of which I made an offset surface to create a solid half-sphere.

Using QuickSlice to create slices of my shape, I attempted two orientations: vertical and horizontal. Vertical offers less usage of the support material, but both take about 3.3 hours to create.

Although I defined my shape as a b-spline, I encountered some shape fill issues at the points where they intersect the extra shapes, like the eyes, and at the point where multiple splines converge. Luckily, these errors were very small when sliced, and I only had to modify a few frames by deleting an extra curve in QuickSlice. Luckily, my shape had no "yellow" curves when sliced.

Vertically Aligned

Download STL
Download SML
Download SSL

Imported STL (Vertical)

Sliced Bell (Vertical)

Sliced and Supported Bell (Vertical)

Horizontally Algined

Download STL
Download SML
Download SSL

Imported STL (Horizontal)

Sliced and Supported Bell (Horizontal)