ATEC-FAB UTDallas : Shelandy Ting: Project 2: Flashlight Sleeve

My original idea to design the flashlight sleeve is to mix iconic expression with textual expression. However, under the constraint of techniques, budget and time, at end I revised my design to use only iconic expression without mixing the text. Yet it still preserves the essential techniques I'd to experiment to see how much I can push to fit the 2D iconic expression to a 3D surface using FDM. It is a long journey and I got the comment from Andrew Scott that I am "chewing an elephant" and I have to take it "bite by bite." So I'd like to document the details of process so newbies can also chew an elephant like me. Here are some screen shots at various stages.

Naked Edge Check

Material organization for Keyshot

I use glass texture to render top pedals, ceramic texture to render the rose on side and metal for the black body.

During the 3D model construction with the asymmetric "rail-revolve". It is difficult to have a thin layer of pedals on top yet the join to the body is well connected. I did not know I can use Chamfer to relief the problem while I am working on the model, so I compromise the thickness of top pedals to be not too thin because I worried about the supporting issue of the undercut contour. This can be improved in the next time. While turning on the flash light, the non-transparent white-ABS printed sleeve does glow on top part of the pedals, similar to the result I render here using the Keyshot.

For those who are not interested in the journey, just read the week 5 or 6 and jump to week 9 and 10.

-------------------------------------------------------------------------------------------------------------------

Week 5 :

Since I am not be able to use a beautiful Chinese calligraphic font as my design material in the 3D light tunnel perspective art the previous time. I have been thinking to fit the calligraphic pattern on the surface of flashlight, using the font from an artistic Sung Dynasty emperor in the collection in the National palace museum at Taiwan.

Translate the particular verse "舞蝶迷香徑" showing above into English would be something like "Dancing butterfly wonders in aromatic trace" However, it will be boring just do one-to-one translation from the text to 3D surface. I'd like to replace the character of "蝶 (butterfly)" in sothis me kind of flat butterfly icon, and replace the character "香 (aroma)" into a 3D rose, similar to what Robert Rauschenberg mixing flat and 3D objects in his Monogram.

However, my new expression of mixing styles will still keeps some mystery for audience like to ponder / associate what is the original text when they see the mixing textual and iconic expression.

Week 6:
I was lag behind the normal progress, due to some unexpected issue of the previous project. It also let me realized that the resolution of current 3D FDM printing we can afford is far less than what I need to accomplish my ideal. So I have to compromise my design idea. So no more pure 3D butterfly/flower but 2.5D iconic expression based on text or iconic images.

I decide to catch up by something more advanced techniques, which involves using some kinds of fitting curves on surface and so called "circle-packing" by making "screentone" and other techniques used in 2D-printing on 3D surface. In this way, I can make abstract expression similar to the impressionist did in their strokes,

However, there is no clear vectorized scan of this font I want. I use Gimp to convert the scanned bitmap into a black and white image file. Then trying to use Inkscape to make vectorized curve. The resolution of previous bitmap scan I got is too low. I did try redo it using "fuzzy selection" or "intelligent cut" from the new color scan from in Gimp to smooth the contour. But none of them has a decent result. So I gave up the idea to mix the font from ancient manuscript now. I will focus making the surface fitting of 2D icon on 3D first, then attach the ideal way of using the Chinese font later.

Week 7: Ditch the text now, I just prepare the butterfly and rose images on the surface, then use Inkscape to convert it into vectorized file for using as the mask in Rhino. I've been fought for one day and finally figure out the correct procedure to convert a bitmap to vector file for import into Rhino: Path -> trace bitmap -> edge detection -> update ->ok
Some other setting will likely fail. However, there will be double curves for tracing the edges. It will need some clearing up to remove the false curves, by joining them, remove most of unwanted groups, and split them to remove bad curves. While doing this and study the online information, I realized that there is no simple way to do circle-packing in Rhino. It most often need to install Grasshopper and figure out the way to connect the components.

Week 8:
I try the Rhino script of circle packing by Steven Janssen. It did not work for me because it does not do circle packing for filling a close curves. So we likely have to install Gasshopper and other scripts/plug-ins on our own machine to make it work.

To install Gasshopper, download the latest, (currently is grasshopper_0.9.76.0.rhi), under windows system, double click the .rhi file, windows will call Rhino to install it. Once it finished under Windows system, launch the Rhino. It will ask of the agreement of license. Check the agreement, then the post-installation will finish.

To launch the Grasshopper, use the command line input of Rhino to type "grasshopper", download whatever addon for Grasshopper, then drag and drop it from the windows system to the main window of "Grasshopper", then it will install the drop-in addon.

The tough thing is that most of scripts does not give any proper documentation. You have to enough understanding of how those algorithms works before using this script. While I trying to read those papers, I did some calculation and found out that the working surface is too small for the shapes I like to do circle packing on 1.75mm FDM processing. A 1.75mm distance is roughly equal to 3 ticks on the screen shown below, so most of tiny shape/curve can not be expressed well by circle packing. If I increase the radius of circle, the fidelity on making the abstraction using circle packing to is gone. So I have to revise the design again.

Week9
How can I push to make something different in 3D print, without using the advanced "generative art" technology? I decide to think back making sculpture in the traditional way, such as the way people making the Pillar and windows for Chinese temple...

For making the butterfly and rose a contrasting expression, I use two styles in seal engraving: embossed seal indenting seal. The rose will be made in extrusion like the embossed seal, and the butterfly will be made in carving like the indenting seal. I then realized that I can still making the rose in 3D shape, by varying the heights of extrusion in making the pedals. And the searching the Youtube video on "Revolve" command gives me a new inspiration that I can use "RailRevolve" to make a cure revolving based on non- symmetric revolving pattern. So I can actually make the contour of opening of the Flashlight looks like an edge of flower pedals from the bird-eye view. I used the outer rim of rose as the rail pattern, make a profile curve of pedal, then do RailRevolve based on the outer rim of rose pattern. After I use "offsetSrf" on the RailRevolved Surface, I got a nice 3D pedal. There is dilemma to find the balance between how can I make beautiful sharp pedal edges and not to interfere the hole for the flashlight, I spend a whole day to fine tune this.

Week 10
Fianlly, I use "createUVCrv" and "FlowAlongSur" to layout the rose and butterfly pattern on the sleeve conic surface. After cut the unnecessary parts. There come my secrete garden scene. Shapewave charge me $300 to realize this complex design, so I ask some other company to do it in a less precise process.