Tag: Rhino

From creating 2D shapes to be cut, the class took what it learned in Rhino 3D and applied it to 3D modelling with the purpose of 3D printing our designs.  The assignment was fairly open ended, with the only requirements being that our model needed to have an extrusion, a revolution, and at least one Boolean union or Boolean cut operation in it.  After some deliberation, I decided to model the Buster Sword from Final Fantasy VII for my project.

There were several reasons why I chose this besides just being a cool sword.  Because the sword’s design is very geometric, I knew I could have a rough model of it done very quickly and use that to figure out any quirks involved with Rhino models.  Once I got to the polishing phase of the design, there was also a wide variety of extras I could work into it depending on how much time I had left.  The Buster Sword has seen several redesigns in its appearances, going from what is essentially a steel slab on a stick in the first game to a more ornate design with engravings and embellishments in more recent appearances.  By starting with that most basic version of the sword, I was able to gauge how much of those extras I would be able to work in with my time left.

The modelling process seemed fairly straightforward until I tried to save my model as an STL file, which requires that the model be closed.  Apparently, unbeknownst to me, there were many edges that could not join together for one reason or another, as well as a section on the curve of the blade that didn’t fill in entirely.  I chose to tackle the problem with the curve first, since it would be the problem that would be most obvious when fixed.  It also proved to be relatively simple to fix.  After toying with different Rhino tools to make surfaces out of edges and curves, I found the Patch tool to do exactly what I was looking for, while the rest didn’t cooperate with the curve I wanted very well.

Fixing the rest of the model’s problems proved to be much more involved and time consuming.  The culprit ended up being a concept I was not aware of, that being Naked Edges.  It was my assumption that if I created two surfaces using some of the same edges, those surfaces would be created joined at those edges.  Unfortunately this assumption was incorrect, and led to many edges that were unconnected, or Naked, and weren’t always easy to connect.  At this point in the process it took hours of digging through my model deleting surfaces that touched edges and recreating them to perfectly fit the space I needed them to fill.  This was particularly difficult in several cases where, for reasons unknown to me, edges had split themselves into two segments: one that comprised most of the edge and another which covered the last millimeter or so.

With this taken care of, I decided to spend some time adding a few of the embellishments found in the sword’s later appearances.  The first of these that I did was to raise the area around the two slots on the blade to match the hilt’s width, as I found this to be a distinguishing feature of the newer versions.  Next I wanted to do something with the hilt, but was not up to the task of recreating the ornate design found on most modern versions of the sword.  I noticed that the design found in the fighting game Dissidia: Final Fantasy, which was meant to evoke a more classic feel, had five rivets on either side of the hilt.  I was able to incorporate those by creating a sphere that poked less than halfway out of the hilt, then doing a linear repeat down the length and mirroring it to the other side.

The final extra I included was one that I had hoped to be able to from the beginning, but was most worried about: a helical threading winding up the handle.  To start with, I found the helix curve function in Rhino and made the curve extend the length of the handle.  I then experimented with the number of curves needed to get the appropriate spacing, which I found to be three curves going in either direction.  The hard part then was finding the way to turn those curves into a 3D object to add to the model.  In my head this would be accomplished by sweeping a circle along the helixes, but this ended up creating flat edges at the 90 and 270-degree marks on the helix as the circle was fixed in its orientation while it followed the helix instead of rotating along the curve.  After a lot of hunting and almost giving up on the feature, I discovered the Pipe function in a Rhino tutorial, which creates a solid object using a curve and a radius from the curve.  This perfectly solved my problem, and ended up looking very nice with 0.5mm-radius pipes coiling up the handle.

Once everything was joined in a single solid body, I opened the STL file in Makerbot Desktop to prepare the model to be printed.  I had hoped to print the sword standing on its handle to minimize the surface area requiring supports to be printed, however, my model was too tall to print in that orientation and I didn’t want to scale it down for fear of losing the quality of some of the smaller components.  Laying it on its side made the model fit on the printer’s tray, but the rivets on the hilt also meant that almost the entire side I printed it on would require supports in order to print.  In the end, I chose to bite the bullet (or more appropriately, PLA) and print it this way.

The printing process went extremely smoothly.  I chose to print at a standard .2mm resolution with a 20% infill, which allowed a surprising amount of detail.  I had worried while modelling that the threading on the handle would be too small to print well, but was pleasantly surprised by the end result.  Removing the supports was time consuming but not difficult with the right tools, though there is a single support inside of the hilt’s guard that I haven’t been able to remove yet.  Once the rest were removed though, I took some sandpaper to the parts that were held up to smooth them out.  The one part this proved problematic with, though, was the handle.  Because the threading on the handle is so fine and textured, trying to sand the ridges from the supports off of the threads was impossible to do without sanding off the threads themselves.  Knowing now how well the threads came out I would be more comfortable putting the sword on its handle and scaling it down just a bit to make it fit, greatly reducing the surfaces requiring supports and only supporting parts that can be sanded flat without worrying about losing any features.

In the near future I may end up painting this with some friends, and will update this post with pictures of the finished product once I do.  Thank you for reading!

From the model prototype, the class moved on to making a 2D digital prototype to be laser cut out of mat board.  We created this in Rhino 5 using curves in the top viewport, and then sent the file to be laser cut into a phone holder to use for filming later in the course.

I struggled with ideas at first, so I decided to take some scrap cardboard I had around the house and make a prototype for my prototype. Early on I decided that I wanted a sort of U shape for the holder, but had some trouble deciding how I would have that shape hold the phone upright. I didn’t want to rely on the walls of the U to hold it in place both because I knew if I did that then they would eventually bow outward and become useless, and also because that would require very precise measurements, which were difficult to do with the tools I had on a phone case with curved edges. Eventually I decided to use two sticks inspired by popsicle sticks to hold the top of the phone in place while letting the bottom rest freely on the floor of the stand, allowing it to be angled up or down within the case.

From there I moved on to modeling the holder in Rhino. Since I have experience working in SolidWorks, working with curves on a single plane was quite straightforward. I quickly made a base for the U with slits 15cm apart to connect to the walls, which I then modeled along with the sticks. It was at this point that I realized that with the plan as it was, there was nothing to keep the walls from wearing out and falling over to the point that they wouldn’t support the sticks anymore, so I etched some slits where the sticks would be against the walls to secure both them and the walls in place. With that done, I also realized that I didn’t want the walls to be acting as stilts for the entire camera holder, so I put a score across each side of what was left of the section of the walls I cut the slit from. This created a tread that would allow the piece to bend at that point and fold under the floor.

With the structure fully designed, I decided to make a few aesthetic adjustments to it as well. Half because I wanted to save material and half because diagonal lines look cool, I decided to cut a wedge out of the walls of the U shape. I then rounded the ends of the sticks to make them better resemble their inspiration. As I did this, I realized that it would both look good and save me from unnecessary stab wounds if I beveled all of the external corners on the design. With these changes made, I sent my design to the laser cutter for a first pass.

On doing the first cut of my design I was pleased to know that most of it worked exactly as planned, with two caveats. The first was with the hinges I created. Not knowing how thick the laser would cut into the board, I only scored two lines into the hinge. I learned while looking at my first prototype that this single tread did not let the board bend as fluidly as I wanted it to. Fortunately, I also learned that the laser’s scoring is very thin, which gave me more than enough room to fit another line into the design, solving the problem. The second problem was with the slots I cut to slide the popsicle sticks through. I had made them 1.2mm wide, the same as the slots used to hold the pieces together, however I learned that while this width is suitable for when a tight lock is desired between the two pieces, it made it very difficult to insert the sticks through the slot, and even worse getting it through the second one. I took an X-acto knife to the slot, widening it very slightly to make sure that would adequately solve the problem, which it did. After running my board through a second cut I was successfully able to build and take apart the phone holder.

Thank you for reading! I will have images added to this post as soon as I can sort them all out from my camera.