I thought of describing a bit how I do it when I make a prop so here goes. I wont show every part individually as all are made in the few ways shown, either by sculpting (Cerberus heads), foam+plastic+gesso or from random things found at home.
Planning & sketching
The first thing I did was finding pictures of the item I wanted to replicate, preferably in as many angles as possible. I watched Advent Children movie but could not find good enough reference art there, then I checked Dirge of Cerberus but same problem. The angles are poor and the art in DOC has too low resolution.
Later I found a real replica of a Cerberus, made by SquareEnix, in all angles and wonderfully detailed. I have several more angles and close-ups of the very same gun. Here is the concept art (all credits to ShopAnimeDVD/Squeeeeeeeenix):
An important part of propmaking is using your imagination. How can I make this crazy shaped object? perhaps I can use half a flower pots backside glue to a curtain rod decoration adorned with the head from a can of a "Loctite Super ATTACK" super glue? Really, just think of cheap alternatives before buying that expensive item that could look well for your prop.
You have thousands of things at home, many which you won't use so just consider it. You probably have lots of DVD and CD cases and there's some cheap thin plastic right there. You probably have card board, newspaper, old shoeboxes, the cardboard case which you computer arrived in and there's any paper you might need for papier-mâché and so on. Thousands of materials are just lying around and other might be come by cheap if you think it through. Raw materials are sometimes cheaper. Sometimes it's the thrift store that have your materials. THINK. It can and will decrease the price of your props by a LOT.
When you have reference art for every corner of the item you have to plan your way to approach this problem. There are hundreds of curves, shapes and patterns you have to consider and which materials will be best for this. It's hard work and requires imagine without it's like anywhere else. You are about to create what, in general, doesn't exist. You don't have high-tech molds and 3d models available that you can just mold and cast from.
I recognized my two biggest problems to be the barrels width so I checked which dimensions of PVC pipes were available and adapted the proportions of the pattern to it. Next is the details on the pipes and the barrelholders above and below the unique tripple barrels.
I chose clay for making the wolves heads and for the long lines along the pipe.. I'm not sure yet, but I'll figure it out. Considered "3d paint".
When all materials are considered, make a proper blueprint from the side without perspective and one from above/below. I usually scale up a picture to the size I want and trace the main lines on the paper, with help from the light of a high contrasted image on my screen. Just lay the paper against the botton of the screen and carefully trace most of the important lines and finish the rest by hand. Really simple way to make sure it's proportional. I had to redesign the trigger and move it because I would not be able to get a finger in there if I didn't. Just an example of things you have to consider while making it. The blueprint is a guide how to do the REAL version, not how the fictional item is.
Back to the drawing board
Great, so you have a blueprint but it doesn't end here. You have to draw detailed blueprints of all parts separately. I drew blueprints for the trigger, handle, the hammers on the back and the revolver drums.
The other paper where the barrels continued is gone, and no traces of it to find anywhere but it's just for show anyway as I've already used it at the point of the photography.
Now it's just down to building it, the easiest part.. Right? Well it's always difficult to craft things without accidentally scratching or damaging any surface, but atleast this process is straightforward and made easier if you did your blueprints with care.
From pattern to parts
I always look at how things appear to be shaped. Any flat side will later be covered with thin plastic (like styrene or similar) but round shapes might sometimes have to be covered in gesso and sanded down to perfection though this takes a while. The fewer places where you have to sand the better! I basically made things easier by flattening some shapes.
When I was satisfied with the shapes I took the pattern and laid it out on top of the foam board to then trace along the lines of it, pretty hard so that the pattern will be marked on the foam through the paper as I sometimes don't cut the patterns out.
Cutting foam, not fingers
Firstly. As you can see on the picture above I used a hobby scalpel. It's really damn sharp and does cut foam if you force it but it squeals and begs you to stop. I'm one of those who have always whined on "WARNING!" notes and disclaimers yet I'll warn you only once or twice. Seriously, don't use a scalpel or a knife to cut a foam. Not only will the edges be rugged and uneven which makes your work several hours longer, using an incredibly sharp knife on small details and on hard plastic is pointless and more difficult than you have to make it. A hot knife will slice through the plastic like butter and leave it with a nice and smooth edge.
If you pick the scalpel because you can't be arsed to buy a new tool, don't be a tool like me and cut yourself while trying to cut thick plastics in tiiiiiiiny detailed shapes..
When you've gotten your HOT KNIFE use it to carefully cut out the pattern you traced on the foam. Note that it took atleast 4-5 times as long for me because of the horrid scalpel.
With a hot knife you'd have just followed the lines and cut all the way through in a swift move. Really. But I finished it even if it took a while. Just make sure you follow the lines and that step is pretty simple.
When it's cut out, compare it to your blueprint and make sure the shape is good, if not either glue foam on it and reshape it that way or start over on a new piece of foam and learn from your mistake - the material is cheap after all. Do not ruin the appearance of your prop because you did not compare carefully to your blueprint.
Some prefer to paint right on sealed foam but foam have many issues, even if you seal it with glue. Sealing.. that's to say foam covered with something to make sure the edges are smoother and that the color won't melt the foam. I've used insulation foam here and it is easily damaged. If you poke it, it'll be damaged. So what you have to do is reinforcing it and I chose thin styrene sheets (0.3mm) and covered all pretty flat areas with it. When I say flat I really mean all areas that are flat in all ways but one. A styrene strip can be bend can be bent like a "(" if needed, though it can only be bent in one direction. You cannot make a bowl-shape with styrene if you understand what I mean. You could theoretically make a bowl if you heat it up a lot but the type of styrene I have is more likely to melt or be destroyed by heat as oposed to gently forming the way you want, like wonderflex would for example.
This is another piece, the guard around the trigger but the idea is the same. Press any flat side against the styrene and trace lines around it. As you can see all the sides around this piece are flat so all sides can be covered with styrene with relative ease. Just repeat the step until all sides have styrene pieces for them, numbering them carefully so you know where each piece fit and which side is up and down. I do this with numbers, I draw a number on both sides and know that the numbers should be pressed against eachother for it to be the right fit.
Continue making styrene for all flat sides until it's completely covered, this piece needs one more piece to be done. If there is a round part or some side you cannot cover effectively with styrene without ruining the appearance, leave it and cover it with gesso when all the styrene pieces are glued and have dried.
Smoothing uneven edges
I chose to work with a gesso-like substance this time and it worked out reasonably well. Easy to sand and pretty durable but remember that it's pretty fragile and breaks unless supported.
I covered all edges I wanted smoother and sanded it down a few times, 2-3 times is enough. First layer & sanding really rough and then 1-2 more more if needed to smooth it out further. Use really fine sandpaper, atleast 200 grit for the final sanding, preferably 400.
Misc - the drums
The hardest parts can be made easy if you really use your imagination. You'd imagine making three revolverdrums with perfect width, length, shape and material would be difficult, especially when wanting to add details like 8 bullets in each drum.
I was lucky and found PVC pipes of the correct thickness and with cool detailed rings on the side that were of the exact right width.
(one of those are glued upside down but I changed that after the photo) I put plastic over one end so I wouldn't have to worry about that, the other end which would be forward.. I really wanted 8 rounds in each drum and I wanted it visible and cool and so I really thought about it a bit. I gathered bits and pieces and found here and there to make those cool detailsThen I cut out foam bits that that would fit into the drums, stuffed 8 soft air gun bullets into holes I had made in the foam, and then put a piece of styrene over the bullets, with holes so round tips of the "bullets" would seemingly look out :D
And this is the result from that, which when painted will look like a pretty cool and detailed I hope! The three barrels were then made out of 22mm thick PVC pipes, not much to say regarding those really.
Misc - Sculpting
Now to the threeheaded dog of legends, bestowed upon the barrels of Vincents gun. What better way to show that the gun indeed is powerful? Great job by SquareEnix. Unfortunately this doesn't help at all, it is so damn hard trying to recreate what they make, but perhaps that's why it is so fun in the end!
I decided to first try with clay that you dry in the oven.. Well.. it didn't work so well. There were a bunch of problems but I finally decided to try with airdrying clay.. What a mistake. Imagine trying to recreate something incredibly difficult and add a short time limit. After ~10 minutes the clay is already so dry that it will break here and there.
I started off by making a "pattern" again, as I'm really poor at reconstructing things without visual guidance. I have awesome imagination but it forms better in words, rather than creating shapes I can't see in front of me I guess. Anyway, here's my drawing:
After that I proceeded to the process of making it in clay which well.. I suppose it went alright but the problems are not sorted yet. I have not decided how I'll do the wispy legs, smoke and tails on the cerberus heads.. Perhaps 3d paint? I'll come back to that later ^^
After tracing the pattern into the clay I started cutting out the pattern and then proceeded to reforming the body a bit.
These are the mean pair of Cerberus heads I have created so far but they really need those wisps around them to get the right feeling. I'll see to that soon, no worries! Though I really like those teeth, they came out better than I thought, the failure of their noses will be remade, so I think they'll turn out just fine.
Putting some things together
While some pieces works best glued together, some parts don't. For the ones that does, put them together! Enjoy your prop looking a bit more like it's supposed to, but don't glue things together just for the sake of it. If you glue everything together before painting, there's a chance that some areas won't be possible to be painted. Atleast spray the pieces black so any later unreachable area (which is usually in shadow) is not a highly visible color like pink or white.. This way noone will really notice that you were not able to paint that part.
This is the handle for the gun, with the bolt/screw and chain as details, and trigger & guard in place. It looks pretty alright to be fair. All the edges are smoothed too and I'm happy with the overall appearance so far, it looks like this will be a lot better than my last attempt. I've still got the sculpting to do so I'd better not jinx it just yet xD
Click on it for a bigger picture. These are all the pieces I've currently assembled, all that's left is the final head of the cerberus, the top one. Then they will get a lot of those wispy legs and tails that adorn the barrels. After that it's time to paint to finally end up with a proper finished prop!
Here are the raised designs on the barrelholders or whatever it is. I made them out of hotglue because of lack of time and money, else I'd have used 3d paint which is much more smooth and easier to apply like you want it. If you miss with hotglue.. Don't want to think about it.
Painting & finish:
Finished priming the first couple of pieces. All areas that are hard to paint once assembled anyway.. I don't white or pink areas visible that you can't actually reach with a brush.
Most of it was then painted black again to reinforce the paint and further add a somewhat uneven and "worn" look. For the parts that were supposed to be painted silver I used a technique called "drybrushing" which means you used a relatively hard short brush with only a little paint on it, then you brush off most of the paint on some spare paper or so, then you just roughly draw over all the pieces you want to look like they are made out of a silvery/metalish color. It will leave shades in the lower areas while painting the areas that stands out. I've found this is the best technique to make things appear like they are made out of metal. Just a flat silvery color can look good but in general it looks better with the worn look that "drybrushing" gives you.
The plate behind revolverdrums was painted gold and the handle was painted dark brown, it looks like grayish because of the horrible picture but it definately IS dark brown :P
The guard around the trigger and the trigger was lost during the convent and the one in the picture is actually just a placeholder which I made in the middle of night between day 2 and 3 at the con. It is slightly too big if you compare to what it looked like in earlier pictures on the unfinished Cerberus, but it still looks pretty good and I got MANY compliments about it.