Monday, February 4, 2019

Combine Metro Cop (Half-Life 2) Part 1: Helmets

The Half-Life series has always been one of my favorite game series, and Half-Life 2 in particular has a special place in my heart. After all, it's the reason the first prop I ever built was the Gravity Gun. From the beginning I knew I wanted to some day do a group of Combine from Half-Life 2, and I knew I wanted to do them the right way.



Nine months later, I feel like I succeeded. Well, on the first group of Combine at least.

Let's go back to the beginning. Early in 2018, I contact a friend of mine Alex Winslow to see about getting some high quality 3D models made of the various Combine helmets - the Civil Protection (AKA the Metro Cops), the Combine Soldier, and the Combine Elite. After taking a ton of references from the game, pulling the game model and materials, and throwing in some of my own personal design ideas, Alex delivered these models to me.



They were perfect.

I immediately set out 3D printing the Civil Protection helmet, using a combination on FDM and SLA printing. For those of you who aren't familiar with those terms, FDM is the typical plastic printing that you see most people have in their homes or workshops. SLA printers are less common, although they are certainly gaining popularity. They use a UV curing liquid resin to print parts and the print quality is exponentially higher.




I used SLA printing on some of the incredibly fine details for the Metro Cop helmet, specifically the "ears" as well as the gas mask parts. The rest of the helmet was printed in ABS on my fleet of FDM printers. A couple days later, and I had the base helmet finished.



From here it was a typical round of body shop work on the helmet - sand the base print, apply filler primer to fill any remaining print lines, sand the primer down smooth, add spot putty to any left over imperfections. I knew I wanted to cold cast these helmets to give them a realistic metallic luster, so I also went ahead and applied a wet sandable automotive primer and wet sanded the helmet to a glossy finish.



Having gotten familiar with the limitations of FDM printing, I had planned from the beginning to use model making techniques to add in additional details, and use the 3D print as a base form. On the back of the helmet are these rib and dome detail sections. Rather than 3D model and print them, I used thin pieces of styrene tube and some half dome scrapbooking accents to add the details I needed. The result was exactly what I had hoped.



After several rounds of priming, sanding, and filling, the helmet was ready to mold. Having just one Metro Cop would be fun, but having a whole squadron of us would be even better. Molding and casting the helmet presented some challenges, since again I knew I wanted to cold cast the final helmets, which would limit where I could have seam lines. The helmet also has a very pronounced "duck bill", so the mold would be very deep and difficult to pull out from.




In the end, I opted to create a 2 part brushed on mold, with a 3 part mother mold. The 2 part mold would hide the seam between the 2 halves of the cast, and the 3 part mother mold would allow me to more easily remove the "duck bill" from the mother and the cast from the mold.




Several days later, the mold was finished and the first test cast came out flawlessly, I started production on the run of the helmets. The helmets were made by first brushing in a coat of aluminum powder to give the cold cast metallic effect, and then by mixing and pouring several small batches of roto casting resin (Smooth Cast 65D from Smooth-On). A final coat of more rigid resin (Smooth Cast Onyx from Smooth-On) was applied last, to help the helmets avoid warping over time as 65D has a tendency to do.



The detail parts that were printed on the SLA printers needed nearly no cleanup, and so went straight to silicone. These were created using simple 2 part block molds, and would be cast solid. The ears were cast in a semi-translucent resin (Smooth Cast 326 from Smooth-On) with a small amount of green tint added. The ears in the game give off a faint glow, so I wanted these to be translucent so that I could back light them once installed in the final helmets. The gas mask details were also cold cast with aluminum powder and a regular casting resin (Smooth Cast 300 from Smooth-On).





With all of the casting was complete, the set of them were cleaned of their flashing and excess resin (such as where the lenses needed to go) using a rotary tool. The "neck seal" of the helmets were masked off using masking tape and plastic wrap, then painted in a flat black. The lenses were created using some smoked acrylic that I had on hand in the shop, cut in to shape and glued in to place using cyanoacrylate glue. The gas mask and ear details were fitted and glued in to place using epoxy. The helmet fronts and backs were attached together using velcro along the ridge line, where the front seats underneath the back.




Lastly, the helmets were given a wash in watered down black and brown acrylic paint, which was then quickly wiped away, leaving grime and dirt in the recessed areas. Then the helmets were polished using #000 steel wool, which brought the metallic luster of the helmets to life. It's actually incredible how different lighting conditions can make the helmets look completely different from one photo to another.







I was very happy with how they turned out, and I really felt like I had brought the Civil Protection to life with this build.

After the helmets, it was on to all of the weapons and accessories.


More from this build:
Part 1: Helmets
Part 2: Weapons and Accessories
Part 3: Fabric Parts and Final Reveal


Watch the build documentary on YouTube
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Tuesday, March 1, 2016

Building a RepRap Wilson

I really love 3D printing. I enjoy the end results as much as I am interested in the technology behind the machines themselves. Having a background in 3D design, it was obvious to me that 3D printing was something I was going to get interested and involved in. But had you told me 5 years ago that I would be building them from scratch, I'd have a hard time believing you. Unfortunately for past me, I've done just that - since November, I have built three printers from nothing.


My journey of self built printers began last year when I started researching various Prusa i3 designs. I had a few things I needed from a printer - it had to be reliable, it had to be sturdy, and it had to have high print fidelity. For these reasons, I wanted a printer frame built from aluminum extrusion (and it didn't hurt that I had a bunch on hand already). I also wanted it to be as close to a full RepRap as possible - no acrylic or machined parts. Some people might consider this a negative, but don't forget I am an enthusiast in the tech as much as I am the finished results.


After doing some research, I settled on an Adapto printer - it had a large build volume, it was built entirely from 2020 aluminum extrusion, and all of the parts were printed. I put together the aluminum bits and started printing things, and I ran into a few snags. The first of which is that the threaded rod I had on hand was larger than what the design called for. While that isn't a big problem - it's simple enough to modify the designs - the new printed parts began having problems where the captured nut would physically intersect where the linear bearings would be. Or in simpler terms - I would have to start majorly redesigning the printer, or buy all new parts, if I wanted to use it.


I was a little frustrated with the process, and around this time, the Colonial Marines group build at Freeside began to consume all of my free time. I had set the Adapto on the shelf to pick back up, where it was untouched for most of last year. Once the group project and the various events for the year was over, I started researching some other RepRap designs. I was planning on rebuilding one of Freeside Atlanta's printers into a new usable design, and came across the Wilson TS. I did an inventory of all of the parts I had on hand, and it turns out I had everything I needed to convert my Adapto to a Wilson.


I was building The Kraken and my Wilson in tandem and the build was a breeze. The instructions online from mjrice are pretty good - his videos are for the 10mm smooth rod version instead of the 8mm ones I was building, so parts differ a bit - but having put together both my Folger Tech 2020 i3 and doing a lot of work on my LulzBot AO-101 and Freeside's AO-100, I knew my way around how to put a printer together.


I did decide to make a few modifications right away. The first of which is to help the structural support of the machine by adding in some hidden corner braces in all of the 2020 corners, and L brackets where the X-axis and Y-axis frames meet. This helps make the printer be extremely rigid and the prints that come off of it look amazing. I also added in an inductive sensor for the Z probe to enable auto bed tramming, a feature on the LulzBot Mini that I am totally in love with. Having your first layer always be perfect without much interaction is a real dream come true, even if the initial setup is a bit of a hassle.


I purchased an LCD screen with SD card support so that I can run the printer without having my laptop connected. This is an important feature for me since I am often running all of my machines simultaneously, and I don't want to have my laptop permanently attached to them. On my Wilson I am using a RAMBo board, and setting up the LCD had some pitfalls. The Arduino board library has to be modified in order for the RAMBo to properly output to the LCD. Here's the article I found on doing just that.

I added a top-mount for my filament spool, but I may actually take this off as it seems to have created a really unbalanced load. Running the printer at the speeds I had while the spool was on the table causes it to vibrate and move around a lot. I'm going to slow down the printing a bit and try to tune the feedrate, jerk, and acceleration settings. But having a really slow printing machine isn't a lot of benefit to me so hopefully I don't have to slow it down too much.



I've only been printing on the Wilson for a couple of weeks and I'm really happy with both my Wilson and Freeside's "The Kraken". For my next printer I am going to look into the Wilson 2 which improves on the current design, and given how great of a machine this already is, I think the Wilson 2 could be an outstanding machine.


Here are some links to the parts and designs used for my Wilson builds:
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