Sunday, July 25, 2010

This Weekend's Project: Annual Hip Surgery

This weekend, I tackled on a problem that's been plaguing the girls since their first iteration: deficient hip structures. The current build utilizes ball joints. I had some time to think of a new solution, assisted by the plethora of new construction methods I've learned from building the Team Fortress 2 doll set.

The hips have been a problem for one reason: they required to bear significant load on a small region of material. The hip requires a good deal of stiffness to resist torsion, bending/fractures, and friction to keep position under load. Prototype build 1 utilized screws and pins to hold the hip together using a hinge joint linked to the body by a pin. Really primitive, and the movements were restrictive and counter intuitive to the user.

Hip Iteration 2 played with ball joints. I had them aligned in two configurations (cup axial and perpendicular to the ball/shaft) and under three total designs. The problems with the ball joint were apparent: Friction was unreliable. To obtain the correct amount of friction, I had to balance the diameters of the ball with the socket ( often done by shimming with scrap paper) with the friction of the ball and the connector shaft.

Here's the current build. Note the paper used to shim the gap between the socket and ball.

The goal was to allow for maintenance by allowing the leg with the socket to be removed from the ball, and if needed, the ball could be removed from the shaft. This was critical back then due to the way the ball was constructed: poorly. I required a method of allowing maintenance in case the ball sheared apart or deformed significantly, or if I required a complete mechanism overhaul. Handy that I designed for interchangeability and easy modifications back then.

The ball's biggest problem was that despite being able to craft them with a relatively decent degree of accuracy diameter-wise, they were very difficult to make respectably spherical. It was more like building an octagonal cross sectioned polygon. When moved, the "sphere" had more friction in some positions than others.

The second problem was the nature of the material itself. Paper does compress to some degree, and the irregular sphere deformed a lot. It deformed from moving around the socket, with the thicker sections of the ball compressing the socket, making a depression with low friction. The whole setup was susceptible to expansion effects. I noted a fluctuation in friction over the year, attributed best to humidity. Naturally, water will expand paper. The socket was made of Magic: the Gathering (for the smooth finish to assist movement) and the ball was made of 110 lb cardstock. The dissimilar materials caused a more drastic change of dimension than if they were similar. I'm presuming the 110lb cardstock deformed the most, but I have not been certain.

As a result of the problems, I encountered another problem: shaft torsion. Friction was uneven from the ball/socket and ball/shaft interfaces. Some cases occurred where the friction was fairly strong and a degree of torque applied to the system did not transfer to overcoming static friction of the system and went to torquing the shaft. As a result, I had a fair degree of axial play that no amount of shimming could correct.

Now we have the major problems identified:
  • ball irregularity
  • friction irregularity
  • shaft torsion
we can find a proper solution. For normal 1:6 scale figures, the answer is simple: hinge joints mounted to the hip by a rotational shaft/disc system. But I don't have the luxury of the strength of plastic, nor the design space to allow for that. Any part failures required some degree of destructive maintenance to access the failed part if I chose to go the traditional route. This is where Iteration 5 comes in.

Iteration 5 is similar to the traditional hip structure in that it uses a hinge joint and a rotating shaft connected to the hip in a "T" fashion. It however opts to put the rotation within the hinge than at the hip. Iteration 5 uses the strength of the screw hinge system to allow for easy adjustable friction and bypasses the ball-and-socket system and its resultant problems. Shaft torsion has been reduced by shortening the connector shaft. Less length, less torsional effects.

The system has the shaft inserted to a 6mm deep cup located on a notched region on the center movement disc. Disc is shown above the finished assembly. The hinge system resembles a "Pac-man", with an arc removed to allow for clearance of the cup. The cup moves along the arc, limited by the hard stops. Friction is easier to control, as there's only one factor for the rotational aspect. However, the engagement is less (10mm from the ball and socket, 6mm in this configuration) so the shaft needs to have extra friction to hold the same positions as the previous iteration did.

After some initial tests, I decided that my design was worth implementing, at least to one of the girls. Since I'm rather fond of Hotaru having legs, and Aelia isn't really doing anything important, I chose Lia as the test subject.

To construct the legs, I did the usual bit of tubes and shells. I however tried a new method of filling out the spherical void needed to cover the screw/nut part of the hinge: solid hemispheres.
These were made with the handy paper solids maker from long back. I built them in cylindrical steps and sanded them down aggressively with a Dremel. The tube and shell method will be glossed over here since it's fairly simple: glue tubes and reinforce with a sheet of Magic card.

So, how do the finished legs/hips look?

"Don't get any ideas, I'm technically only 2 years old."

Gratuitous upskirt photo time. The new joints solve a cosmetic problem of filling in a small unsightly gap between the thigh and the hip structure. I've left the port covers for the fasteners unsanded for easy access/maintenance.

"Hooray! I can... do the same things I could do already..."

As for evaluation: they are fairly stiff to allow the legs to retain their position. I'm going to see how humidity effects affect the system before retrofitting them to Hotaru and Aelia. Lia will be testing the system and finding any flaws over her next few months. The system does have drawbacks. The mechanism only works for fairly large sphere/hinge joints (mine was 18mm in diameter, and does not work for smaller diameters) and there's a good chance of the torque from moving the legs unrooting the shaft from the hip. I had to re-attach the shaft to the body after noticing the new hips had twisted the shaft out of place.

Monday, July 19, 2010

Painting the Hellfire

I've always hated painting.

To paint the Maliwan Hellfire, I've had to buy some blue paint to experiment with. I have not owned a pot of blue enamel for about 8 years. Now I have 3. Two of them were useless. I decided to pick up Blue Metallic Flake, since the gun has a shiny blue coat of paint in-game. Probably the most useful color. The above image documents my attempts to get all the colors for the gun. For this painting disaster, I actually required the following paints:
  • Dark red
  • Blue Metallic Flake
  • Aluminum
  • Black
  • Grey
I needed a light blue, a deep blue, pinkish red, black and dark grey. The pinkish red was for the glowing red parts of the gun, but I didn't find any means of making a neon color from what I had. So red it is!

For the light blue, a mix of about 40% blue metallic flake and 60% aluminum worked well. An even balance got me a teal color that didn't fit. Dark blue came out with something a bit more obscene: 5% red and 95% blue metallic flake. Any more red and it becomes purple. Some parts required a dark grey, and since I ran out of Gunmetal Grey, a 60/40 mix of grey and black worked fine.

To mix the paints, the surface of an untreated/unsanded Magic: the Gathering card works great. I sacrificed a Crazed Goblin for this noblest of tasks.

The hardest part was probably getting the paints to not look like crap as I tend to do. The dark blue metallic mix tended to run the most and I had trouble getting an even coat. The rest worked fine. To make the finer details in the parts, I etched/scored panel lines with my ever-dulling X-acto knife, and filled it in with a 2 micron achival art pen. Art pens don't like being used on enamels, I learned. There goes another $3 pen! Something clogs up the tip that I can't remove or fix.

The most pain in the ass details were the red glowing parts. In my case, red solid matte lined things. A coat of gloss should fix that. But I'll need to buy that first. Instead of painting them directly on, or making a shallow recess for the paint to remain in, I chose to go the lame route and make pseudo decals. I wanted something on the gun to look somewhat straight. I have the painting skill of a 3 year old child holding an active firehose. If it's not supposed to be going all over the place, I'll need all the assistance I can get.

I painted a sheet of regular printer paper red, then cut 0.5-0.7mm thin strips.

With that, I trimmed them down to length, and applied them to the gun using reckless blobs of adhesive and really fine tweezers for the small red squares. Looks better than any paint job I could have had someone else do for me.

After a lot of painting, panel lining and gluing red things, I finally finished most of the parts. I didn't get to paint my favorite magazine, Mag 3, because it turns out, I mucked that part up and didn't get all the details made. I'll revisit that later.

Monday, July 12, 2010

Hellfire Construction Progress - July 12

Construction on the remaining Hellfire SMG bodies has begun. Body 5, designated HX, has been completed. All that remains are Bodies 1-4: the TD, KKA, TEK and RF designations. Body 1, despite being the most mediocre in game, is by far the most difficult to build due to the fragile sight mounting region, with the windowed frame. I had difficulty constructing the top sight rail for body 4, and that consisted of just a slit with two holes.

Figure 1: Patrol SMG Body Schematics

Here's the remaining schematic for the Patrol SMG series. A lot of the details need to be supplemented by in-game screenshots. I've detailed all the necessary information I need to get construction going, which means some of it will be ambiguous to the causal builder.

Today, I'll be documenting construction of the modular rail system used for the Maliwan Hellfire.

Figure 2: Starting the Laminate Tracings

This portion details the construction of Body 3: the TEK series. With the diagrams from the previous section regarding the rail details, I've traced out the TEK body and overlaid the internals on the tracing. A slot for the magazine 5mm deep and 9.5mm wide can be seen in the tracing in Figure 2. Provisions for the rails have been shaded as a guide.

At this stage, I've gone into a color-type card system to help differentiate pre-glued card thicknesses. Usually, I use 4-card thick stacks documented here, but this project necessitated the use of 2-card thick laminates. Conveniently, I have a crapton of X-Men TCG cards to use. As a result, you'll be seeing a lot of multicolored sections. Magic: the Gathering colored parts are 4 cards thick; X-Men blue means 2 cards thick.

I'm taking advantage of thicknesses by carving and peeling layers off laminated cards to avoid cutting multiple tracings.There's a small recess for the magazine on the outer layers, about 2 cards thick, shown in the above figure.

Here's a view of the layers assembled partially, allowing you to see the individual thicknesses used to make the rail system. A narrow 2mm wide "rail" goes on the bottom and interfaces with the grip's "T" shaped rail. The regions in contact with sliding parts were left unsanded, to let the default coating on the cards have less friction and wear when sliding. Once the layers are assembled, there's little hope for repairs.

Test fit of Stock 3 and Grip 3 on Body 3.

Another view of the sliding rails.

For attaching the Fire elemental accessory to the body, some structural assistance was required. I was essentially gluing two rounded objects together, leaving little point of contact. To minimize future re-gluing repairs, I opted for metal rod reinforcements. 5mm long rods were made from a paper clip, and holes were drilled into the surfaces to be mated. Loc-Tite glue kept the pins into the holes. Once the two parts were joined, the metal pins would reduce problems associated with shearing to a minimum.

Semi completed TEK body. Details were achieved by carving out large sections, then assembling strips of card or cardstock into the cavities. The raised elements in the center of the body were achieved with a single layer of cardstock on a MtG card. At this scale, small bumps can be modeled by the thickness of cards. Some details require etching or peeling a layer partially. Some details require carving, as demonstrated below.

The rear section of the body tapers on Bodies 2,3 and 5. The TEK series tapers from 5mm to 3mm. To handle the taper, I've marked off the material required to be cut, using a black marker. This body belongs to the KKA series, Body 2.

Magic cards behave like plywood, and this can be taken advantage of in carving sloped surfaces. You can use the edge of a knife to slice away at the card stack, thus revealing the individual layers that comprise the card. Approaching the surface at a shallow angle, you can peel off layers lightly.

When you carve, you'll see lines due to the different layers of the individual cards. You can use these lines to judge your surface's flatness by seeing how uniform the lines are. You ideally want straight lines and uniform separation. However, any deviations can be solved by light sanding or gluing a flat surface on top of the slightly uneven one. I'm just going to sand it down, since minor unevenness won't be very noticeable.

Here's the current assortment of parts, semi-grouped into part number. I'm debating making 5 total grip sets and having 5 individual SMGs, but I'll never need all five assembled at once ever.

Here's all the parts available so far, separated. I'm missing five of the 20 parts and it's still workable for a good assortment of combinations.

I'm getting rather fond of the TEK body. This configuration's the TEK 400, with the less popular "Thumper" magazine. Unfortunately, due to the way the grip is designed in the actual game, most 1:6 scale figures cannot properly hold the weapon. A similar configuration would be the FN-P90. Not a lot of figures can hold that gun properly.

Depending on circumstances, I'll either move onto priming the parts for painting, or attempting Body 1 and Stock 1: the most pain in the ass parts to build.

Monday, July 05, 2010

Celebrating July: Maltese "Build a Modular SMG Month"

Finally got around to working on something for a change. There haven't been any other projects worth pursuing, despite playing a game that offered 13 million gun possibilities. A different scope or magazine does not mean an entirely different gun. We call that an "accessory". Borderlands was a rather disappointing run after you realize your weapon never matches the level you're at ever, and the best loot gets acquired long after you're bored with the story missions. "Hooray! I got me a TD52 Cobalt Tsunami! I can use it on that fun mission that I can't play now because the mission was a one time event!"

Anyways, enough of that mess. I've secured my first trophy, Sledge's Shotgun, since that gun was notable in appearance and function. However, my second trophy is distinguished by in-game function only and has 750 variants (150 if you remove magazine choices), and is visually identical to a generic version. It's the only other gun worth considering: the Maliwan Hellfire. In particular, I'm interested in the HX (body 5) version, Cobalt material grade. To better explain the scope of this project, let's bring on some diagrams!

Figure 1: The Pain Begins.

The above drawing is the preliminary planning for the gun. Since I don't want to build 150 versions of this gun, I'm going the modular route and building interchangeable parts. There's 5 different bodies, 6 stocks (counting no stock), 5 barrels, 5 magazines and one grip to choose from. (Maliwan by default is grip 3 for SMGs, therefore there is no option for that to choose from). This gives me an idea of what I'm looking at in terms of total parts to build.

The next phase of building is taking reference photos and scaling profile shots for use in drafting up schematics. Only problem is that there's no sense of scale in the game to use, and the gun wasn't designed to be ergonomic, based on preliminary fit tests. This resulted in an understanding that the g43 standard I've been using omitted a critical weapon category in determining scaling: bullpup configurations. I have not factored in ergonomics for bullpup rifles, which the Patrol SMG fits in, shape-wise. With some rough estimates from other rifles, I've accepted that a comfortable bullpup config has a 1:6 scale length from stock end to middle of the trigger of anywhere from 6-7 millimeters. This value gave me more variance than I liked. I settled for a reasonable and comfortable 6mm distance and set out taking screenshots.

Figure 2: Welcome to Hell. Fire.

I'm focusing on the HX designated body 5 for now. Bodies 1-4 will be built later. Screenshots were compiled by running through a glitched Armory level and picking up every Maliwan SMG in every chest for a good sample population, then chucking them all to the ground. Could have gathered them with the save editor, but that's no fun. I figured out the naming conventions for patrol SMGs in the process, which are detailed in Figure 1. Body 4 for Maliwan SMGs was the rarest for me, as a side note. The following diagrams were drafted for the key parts:

Figure 3: HX body laminate construction

Figure 4: Barrels

Figure 5: Body 5, Barrel 4

Figure 6: Magazines and Grip

Figure 7: Stocks

With that out of the way, It's time to build stuff. Figure 6 details the actual mechanism used to connect all the parts together. A T shaped rail integral to the grip will hold the barrel and body together. This piece required reasonable uniformity in spacing throughout. I found that a 2mm wide rail 2 cards thick retained enough strength to not shear off during repeated use.
The stock uses the same mechanism to hold into place with minimal wobbling. Here's a photo of the individual layers of stock 4. The middle layer has a notch to accept the mounting rail part. All sections are 4 cards thick.

Gluing stacks of card together is trivial to explain by now. I'm confident you all can glue 12 cards together and cut them. Parts here were built with some modifications to the diagrams from Figures 3-7.

Test fit of the HX430 config. No barrel has been built for Barrel 4 yet.

Test fit for Stock 3, in the HX 330 config. Stock 3 and 1 are the most unstable to build due to their low amount of material.

Stock 3 consists of two rods with notches that fit onto the retaining rail for mounting the stock. Not doing so would allow it to shear easily. Other options involved drilling holes and reinforcing with paper clips, which is what I did for the rear part of the rods.

I've started on the details for individual components, after being satisfied with how the parts fit together. At this stage, I've completed magazines 1,2,3,4, barrels, 1,2,3,4, stocks 2,3,4,5 and body 5 and tested for compatibility with each configuration. Time to etch out the grip details.

The grip has a few uneven layers that need to be carved. I took care of the larger noticeable side profile depressions by tracing them on with the template shown in the middle. I used an X-acto blade to cut out a groove, then peeled off the card layers gradually until the desired thickness was achieved.

After some carving, this was the end result.

The HX230 is looking better with the semi-finished grip. At least it matches now. Time for some part roundups.

HX 100, with barrel 1

HX 220 with barrel 2

HX 330 with barrel 3

HX 440 with barrel 4

Stock 5 was built, but I wanted to illustrate the parts with similar numerical groupings. Barrel 5 and magazine 5 have yet to be completed. After those are completed, work may begin on the other bodies.