My friends and I frequently play table top games together. We have multiple games running, each with game with its own papers per character per player. These documents are getting more difficult to manage, so I decided a computer dedicated to our games was needed. Portability and power were driving forces in the hardware selection, but not as much as striking design of the case. While looking for inspiration on case modifications forums, the biggest departures from a standard rectangular case were computers mounted on walls with component connecting cables being routed through drywall; not very portable. I looked to our game boxes for inspiration and noticed many of these games used die with greater than six sides.
Looking through all the gaming die in my collection while considering how to construct these shapes around computer hardware, I decided to base my case on a twelve-sided dice for several reasons. The radial symmetry would better allow for modular builds. The pentagonal faces were large compared to the whole shape, only beat by the four sided and six sided dice. This would allow for easier installation of hardware. The dodecahedron also struck a balance between spherical silhouette and complexity of construction.
The case would be comprised of 3 distinct categories of parts. The Support Frame; something to hold up the weight of the computer hardware, the Panel; to conceal the case internal and provide mounting points for hardware, and the Case Frame; the object that would connect the Support Frame and the Panel.
--------------------------------Case Frame--------------------------------
I used Maya's Solids menu to create a platonic dodecahedron and exported it as an .obj file into Rhino. Points were placed on each vertex. On a separate layer using the Line tool, I drew lines between the vertices to create the edges of the shape. Next, a point was placed on a separate layer in the exact center of the dodecahedron. Lastly, on yet another separate layer, I placed points on the center of each face. I then locked these layers in a parent layer named Reference Points. This was done to break the solid object into basic geometric components I would need to interact with when orienting tools and to aid in general model creation and manipulation.
The next step was to measure all the mounting points of the computer hardware and create to-scale models of the hardware to be placed in the computer case. Knowing generally how much space a given piece of hardware needs for adequate airflow, I brought all the hardware models into the case file, placed the models as close as possible to each other, and scaled the Reference Points layer enough to encapsulate the hardware model.
To create the Case Frame, I selected all the edges of the of the
Reference Points layer and used to the Pipe tool to create 3/8th in thick rounded-cap pipes. I used Boolean Union to merge all these edges into a solid frame.
With the Case Frame selected, I created a negative space that matched the panels placement on Case Frame using the Boolean Subtract tool. There was a problem. The Case Frame is rounded, and the panels were inset slightly towards the middle of the object to obtain a smooth flow from Case Frame to panel. When the recess was modeled, there was a slight lip overhanging the panels that would prevent them from sliding into place. This took a long time to fix because I had to explode the Case Frame, select each side of the recess individually and copy-extrude them through the overhang. This extrusion was used as a cutting plane to split the overhangs from the Case Frame. Then several hours were spent patching sixty gaps that were a thousandth of an inch thick using the Line, Planarsrf, and Join tools. If these gaps were not fixed, the model wouldn't be solid could not be printed.
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| Render to show the surface clipping between panel and frame overhang |
To complete the Case Frame, I needed to create screw holes so the panels would have a way to be secured. I created screw holes 1/4 inch deep that would fit a 10-32 machine screw. These holes where placed centered in each corner of each panel recess by drawing correctly sized circular curves and extruding these curves to the right depth. These extrusions were then subtracted from the Case Frame.
Lime Green: Radiator Fan
Bright Red: CPU Radiator
Dark Purple: Motherboard
Light Purple: Support Shelf
Brick Red: Graphics Card
Blue: I/O Block
Orange: Hard Drive
Olive: Power Supply
Dark Green: Case Fans
--------------------------------Support Frame--------------------------------
It was time to start on the Support Frame; the shelf that supports the motherboard, graphics card, and hard drive. This was done by drawing a line with the Line tool straight up from each bottom vertex. I then connected the top of these lines to the next row of vertices to create a more structurally sound design. I then made these lines solid using the same method as the Case Frame. I then used Split and PlanarSrf to flatten and cap these struts to give the motherboard shelf a level place to be secured to with screws.
The last piece to add to the model was the power supply unit (PSU) support. The PSU was design to rest its weight on the inside of the bottom panel, but there would be extrusions from the Support Frame to prevent the unit from sliding around. These were made my drawing lines on the surface of the PSU that traveled through the mounting holes. I used the Pipe tool yet again to create a solid that covered each hole of the PSU. I then extruded solid the curves that made the mounting holes of the PSU through these pipes and subtracted these extrusions from the pipes creating holes for screws to pass through. Finally, these pipes were connected to the Support Frame by using Line, PlanarSrf, and Extrude tools to create angled connectors that would not impede screwdrivers from accessing the holes. This completed the Support Frame.
--------------------------------Panels--------------------------------
Using the PlanarSrf tool, I selected the edges that composed a face and made a pentagonal plane. I moved this plane to sit on the outside of the Case Frame, then scaled the plane down to reach a size that showed just enough of the Case Frame. A solid extrusion of the pentagonal plane was set to 1/4th inch thick. I did this for the eleven remaining faces. This was one of the many times I used the the
Reference Points to ensure the tools moved along the normal of the face I was working on by selecting the point that represented the center of a face and the center of the model. The screw holes in the panels were made by selecting the curves from the Case Frame screw holes and extruding them through the panels. These new extrusions were subtracted from the Panel solids.
There were solid panels, a front panel, fan panels, a radiator panel, a PSU panel, and an I/O panel. The solid panels were complete, and the fan and radiator panels were just a matter of extruding a few more screw holes and subtracting like before. The front panel need a hole for the power button, which was done by place a circular curve in the middle that matched the diameter of the power button. The PSU panel was completed by creating a hole where the PSU fan would face downwards and draw cool air in.
The I/O panel was the most difficult. I started by place curves around around the I/O block its mounting holes. After extruding these curves, the rectangle was cut and the mounting holes were connected to the panel using Line, Split, and Join tools. For power, A female power adapter was modeled and cut from the panel. This adapter will be soldered to a power cable that plugs into the PSU and allows for normal power cables to be used on the outside of the case.
The design on the front panel was created by using the Make2D command while in a top-down orthographic view of the model. After much cleanup, the shape met the lab-tech's approval.
I exploded each panel to obtain a single plane with all the mounting holes needed. These were carefully rotated onto a flat plane. The outside of each panel was traced with the Line tool and placed on a magenta layer and each internal hole traced with a curve tool and placed on a blue layer. The front panel design was lined up and place on a red layer.
---I/O Block---
A challenge with this case design was how to plug things into it. Due to size constraints, I couldn't place the motherboard perpendicular to a panel and simply cut a hole in a panel for port access. My solution was to create a pass-through. There would be M/F cables running from the motherboard and graphics card to a panel, and the peripherals would be plugged into those extensions. To start, I bought the needed extension cables and modeled the female plugs on each one. Each model was also given an extrusion that was slightly smaller than the plug that when subtracted from a larger solid, would prevent the cables from moving forwards or backwards. With the models centered on a line, a bounding box was placed around them and scaled up to give the print some thickness. Curves matching the diameter of a 6-32 screw where placed perpendicular to the ports to screw the two halves of the block together as well as parallel to the ports to screw the entire assembly into the I/O panel.
---Printing and Laser Cutting--
The printer I planed to use had broken down. The project was scaled down 50% to fit into the Fabrication Lab's printer. This meant I needed 1/8th inch thick panels. Sourcing thinner wood was no problem but the screws were another problem. It took about 32 hours to print the Case Frame and I/O Block and another 24 hours of soaking in bath. The panels took 12 minutes to engrave and cut. There was some experimenting done to find the correct settings needed to cut the two-way mirrored acrylic. To get the laser to cut through the panel, The power was high enough to not only cut the acrylic but shrink the uncut material along the edge as well. To account for this I had to scale the front panel file up by a factor of 1.01.
---Processing the Materials---
With the frame printed, it was time to start processing the object. I started with XTC-3D to smooth the serial ridges of the print. This would be important to produce a more metal like finish. While this smoothing compound was curing, I did test stains on some scrap wood to figure the time needed to obtain the desired darkness of stain. 30 minutes was the longest I could wait. Any longer and the stain would start to dry, inconsistently changing the specularity of the wood.
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| With XTC-3D |
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| Without XTC-3D |
With the XTC-3D still curing and stain time determined, I got to work staining my panels. Once the staining was finished, I left the panels to dry over night in my garage. The next morning I applied several coats of satin polyurethane spray to finish the wooden panels.
Once the XTC-3D was dry, I applied several thin base coats of Jet Black paint by Alsa. Once dry, I used Alsa's MirraClear coat to harden and make glossy the finish. This cured for 18 hours before applying the Killer Chrome paint. In skilled hands, Killer Chrome is capable of producing a mirror finish on a smooth dark surface. I don't yet have those hands. With it dry, I polished the chrome coat with a damp cloth, let dry, and applied the final coat of MirraClear.
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| Checking that paint hasn't built up enough to impede panels |
For the screws, I took sixty small nails, taped them into groups of five, and cut their heads of with a dremel tool. These nail heads were then glued into the panels with Lock-tite. Nearly all the panels fit snug, but the I/O and bottom panel needed a small assist from some double sided tape. A ring was made from a linear foot of RGB LED strip and secured inside the frame to show off the effect the two way mirrored acrylic.
Materials
Satin Polyurethane spray was used for its soft diffusion of light that subtlety displayed underlying wood grain of red oak. General Finishes Cranberry Red Water-based Wood Stain was used to produce a deep and warm earthy red tint to the wood that would contrast to the cold metal finish of the Case Frame and the reflection of the front panel. The front panel is 1/4 inch thick double sided mirrored acrylic pane. I wanted a window to show off the unusual stacking of hardware, but I didn't want an always transparent panel. this mirrored acrylic allows for my hardware to be concealed by controlling the internal brightness of the case. Black chromed 10-32 1/2 inch machine screws are used to affix the panels to the Case Frame. The black chrome complements the warmth of the wood finish and the metal finish without being too eye catching. None external screws are 6-32 machine screws of varying length for threading into computer hardware. The computer hardware is as follows. Also Corp provided the needed paints to obtain a metal finish.
Motherboard: Gigabyte H170N-WIFI
Processor: Intel i5-6400k
Processor Cooler: Corsair H75
Graphics: AMD R9 Nano
Memory: Ballistix Ellite DDR4 8GB
Storage: Samsung 840 EVO 500GB SSD
Power Supply: Corsair SF600
Case Fans: Enermax Magma 120mm (two)
The I/O Block: 1 RJ45, 2 USBs, 1 Wifi Antenna Adapter, 5.1 Audio support (via 3 3.5mm jacks), DVI cable route, and HDMI 1.4
Operating System: Windows 7 Professional 64-bit
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