Ashley D Goodenough: "Lyretail" Prosthetic Accessory

Concept:

My focus for Digital Fabrication this semester is the study, design, and fabrication of various prosthetic accessories for specific uses. My first project, which is for a below-knee accessory, will be a prosthetic accessory for scuba diving. I’m calling it Lyretail (or alternately, Scalefin), because my main inspiration for the form comes from a family of gorgeous saltwater fish called Lyretails, also sometimes known as Scalefins. It’s also a fun play on words, and I’ve become endeared to it. There are many variations of the lyretail, but they all have exaggerated and slightly asymmetrical tail fins, and their coloring tends to be dramatic. My goal for this design is to make a diving prosthetic that echoes the streamlined and elegant forms of oceanic fish. The flipper will be similar to a split-fin in that the paddle will not be a solid piece - it will be for diving in conditions where the tide is less strong and unpredictable and you want a little more fine control of your movement. The lower leg portion of my concept draws from the shape of the wings of a manta ray.

From my research, I’ve gathered that a single-axis foot is what most people want from a scuba prosthetic - this way, the foot/fin only moves in one plane and has a predictable path of motion. Another need is ease of attachment and detachment of the flipper to the prosthetic foot, which in most cases is a Sach foot. Given the limited availability of dive prosthetics out there, it’s fair to say that another desire is more customization of the shell to suit your personal style. With these main ideas, I started concepting the Lyretail. When the model is finished, I plan on the ankle joint being a single-axis of my own design. It will ideally be able to lock in 2 or 3 positions, using some sort of manual dial. Additionally, the flipper will either be modeled in a way that means it can be easily slid onto a foot underwater and tightened around the heel, or it will be modeled so that if it were printed in a flexible and water-safe material, it would be simple to slip on the Sach foot and over the heel. The top leg portion will be completely separate from the flipper, but will be connected to the joint and the Sach foot design that fits into the flipper. 

In addition to my online research of scuba prosthetics out there currently, I also interviewed a family friend who is a recent amputee and a dive master. We met and talked about how his dive prosthetic works, and how I could go about making my final design effective but still appealing. He agreed with the need for a single-axis rotation in the ankle, and liked the idea of a locking mechanism - he’s actually been designing something similar recently for his own use, since he’s an engineer by trade - and the need for the flipper to be easy and fast to put on and adjust. I learned that I either need to create a leg design that is a completely functional underwater prosthetic that can use a vacuum and pressurization to stay attached, or my design must be purely a surrounding shell that can fit around an existing prosthetic. I haven’t decided which direction I’m going to go with that yet. He emphasized as well something I need to generally keep in mind in this business: every single prosthetic or prosthetic accessory is designed for a particular person, because everyone’s situation is going to be a little different - height, weight, amputation level, etc. I’m going to keep meeting with him when I have questions about ways to make my design more useful, or if I’m uncertain about my design interfering with its overall effectiveness.

Modeling (so far): 

My modeling deliverable at the end of the first four weeks of the semester was to have a clean, preliminary model of my prosthetic last; I would have the main form ready to go, and have very little detail. I got a little further than that, but may have to backpedal after talking with my friend and learning about how his personal diving leg works. I started scaling my concept drawings to each other in Photoshop and setting up some visual guides so that I could bring some orthographic views into Rhino and use them as a reference. I used PictureFrame to set up my front, side, and top views. I used Control Point Curves to first build the side silhouette of the leg and flipper together, then the front silhouette, creating only vertical curves for now. I also used my top view concept of the flipper to curve out the shape of the sole. Then, using Interpolate Points Curves, I drew horizontal curves to basically act as defining curves for the shape of the leg and flipper. I needed quite a few, since the flipper was more complex than a normal foot last would be. I used Rebuild to reduce the complexity of my curves, and made sure I still had intersection where I needed it. Using CurvatureGraph, I tested the continuity of my curves to make sure I was going to build a surface that was relatively smooth with curves that were continuous after I had been splitting and joining them. Before I used NetworkSrf to create my last, I split my vertical curves at the ankle, so that I could have separate surfaces for the leg and flipper, given that the leg could be a much simpler surface if I rebuilt it separately. Then, I selected all my curves and used NetworkSrf to build a loose surface. The flipper turned out to not be incredibly smooth, no matter how much I refined my curves (with RecordHistory turned on), so I turned on control points and sculpted it for a while just by manually moving points around (MoveUVN). I also used SetPt to align my loops to get a smoother surface, and Zebra to test my UV stretching. In the end, I also ended up using ExtractIsocurve to pull some new curves from the surface, and then rebuilt again using those slightly better shapes. Now that I had two surfaces, I could start refining. I used Interpolate Point Curves and Interpolate on Surface Curves to mirror my concept art from the side view, then projected my curves onto the surface. I used Trim to remove the parts of the surface I didn’t need anymore, but kept a copy of the original surface in case I paint myself into a corner later and need it back. Once the top of the flipper and the leg were trimmed, I used OffsetSrf (with Solid checked) on the leg to make it a closed polysurface with a width of a little over 1/8 inch. I FilletEdged every edge to almost the same radius. I attached the pole to the open leg design using some fancy cylinders and DupEdge to mimic my current shapes and a BooleanUnion/Boolean2Objects combination. For the flipper, I used my own foot last design to build an inner hole, then used BlendSrf to connect the two at the top. I used Patch to close up the bottom of the flipper, but had some cross sections to assist it in being smoother. Since that patch wasn’t quite lining up with my flipper and I needed to clothe my naked edges, I used JoinEdge to close the tiny gap.

Materials: Given that the model is not complete and separated into its component pieces yet, I'm holding off on deciding on materials. My favorite idea right now is to mimic the coloring and patterns of the batfish, and use a rubber-like material for the flipper and a hard plastic for the leg (the hard molded part of most prosthetic legs is made of carbon fiber):

References:
https://www.media.mit.edu/videos/ceb-2016-05-06/
http://biomech.media.mit.edu/#/

https://www.northeastern.edu/rise/presentations/triton-scuba-diving-prosthetic/

http://www.bizjournals.com/twincities/blog/in_private/2012/11/meet-the-scuba-leg.html

http://www.scubadiving.com/article/news/what-its-dive-double-amputee

http://www.palmbeachprosthetics.com/Stories-dive-buddies-part-iii-14.html

Ashley D Goodenough: Pepakura "On the Surface"

Concept: My Pepakura design is called “On the Surface.” I was inspired by water gardens I’ve been to in DFW and Atlanta, and wanted to recreate the feeling of serenity and peace that the koi ponds at botanical and water gardens have.  I also wanted to play with the idea that the ground could be like the surface of a pond, reflecting the objects just above it and “completing” an image. I designed a koi fish half out of water, swimming between two differently sized lily pads that create balance and visual harmony.

Modeling: I modeled my two objects (lily pad and koi fish) in Maya, then brought them into Rhino for some final editing. After making sure I definitely had a mesh object, I exported both as .objs and brought them into Pepakura Designer. Using Pepakura, I cut both models into strategic loops, then unfolded them and arranged them on the grids. I ended up with two 24x48” sheets for the koi, 2 for the large lily pad, and 1 for the small lily pad. I made sure my edge IDs were visible in Pepakura (and also assigned magenta and blue to the different cuts and folds), then saved a .eps (for edge IDs) and a .dxf (for cut and fold lines) to be combined in Illustrator. In Illustrator, I overlaid the text edges with the cutline/mountain/valley .dxf file, and then brought it all back into Rhino for final adjustments and layer assignments. I had to make some changes to the dot-dash and dash line types for mountain and valley folds to make them distinguishable from each other when laser cut. I also needed to move and resize some of my edge IDs. Since this is my first pepakura project, I kept them all just for some insurance while I was constructing the pieces.

Materials: For my Keyshot renders, I did three passes: a diffuse pass for color info, an occlusion pass for contact shadows, and a shaded wireframe pass to emulate the pepakura look that the piece has in real life. I used Axalta lime green for the lilies and leather for the koi. With the leather texture, I turned off the bump map, changed the foreground and background colors, and increased the scale to 3000. For occlusion passes, I applied the Keyshot occlusion material to all objects. For the pepakura effect, I applied the Keyshot shaded wireframe material to all objects.

White e-flute cardboard was used for my fabricated pepakura, which I then taped off with white masking tape after assembling with Loctite Pro.  I finished the pieces by coating them with a layer of polyurethane, then I painted some areas with acrylic paint, but kept some of the surface unpainted so that you can still see how the pieces were created. After that, I sealed them with a satin polyacrylic coat to give it shine and protect the paint. 

Ashley D Goodenough: Week 10 Waffle Structure

Concept: My waffle structure is called “Tisantaphobia,” which is a fear of tents. Inspired by the discomfort and anxiety some people (like myself) experience when attending formal events, this architectural structure was designed to feel imposing, monstrous, and kind of like a giant trapeze tent beast. 

Modeling: For creating the mass structure, I used Interpolate Point Curves to draw my initial outlined forms that I would build my surface from. I used CurveBoolean and Conic to get the curves all connected and angled correctly. Then, I used NetworkSrf combined with a very few sweeps to build the surface. Contour in both x and y directions got me the basic waffle structure I wanted, then PlanarSrf and ExtrudeSrf made them solids. I used the very buggy CutMyRibs script to create notches that had to be cleaned up extensively (Extend and Split), then the MassiveUnroll script to easily lay them out on the ground plane before placing them strategically on 24x48" reference planes for laser cutting. I wanted to build this as large as I could using the 24x48" 2ply cardboard I had access to, which seems crazy. I very much like the idea of keeping this piece, and it doesn't feel imposing and threatening as a small maquette. 

Materials: I used 2ply cardboard for this project, because it's structurally sound for a large build, and since I didn’t want the print to get more expensive than it had to be (disregarding the fact that it was going to be expensive anyway due to laser machine processing time). I may decide to do a very small model next in two different types of wood, but the end result would have a completely different feel to it. In Keyshot, I used walnut for the X direction and ginger bronze paint for the Y direction, because I like the way the two materials contrasted in specularity but paired nicely in color. Despite its imposing feeling, I still wanted the piece to be beautiful and majestic as a waffle structure, especially when envisioned as a very large sculpture. I also did extra renders using Keyshot’s occlusion material, then overlayed the images in Photoshop using the multiply blend mode. I then placed my renders within images I took of the ATEC building, to put the architectural piece in its potential place of display. I’d like to see this built large enough to walk under. For my fabricated piece, I ended up using plaster fabric to provide more structure to its feet before I eventually paper-mached the whole thing. The paper mache process took much longer than I thought it would, considering its size and the rainy weather we've had the last few days, which made it take longer to dry and set. I then painted the entire structure with a white satin exterior paint to make it feel more tent-like again.