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How to make a Portal Gun

Step 3The main barrel

The main barrel
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It all starts with the barrel of the device. This measures up to a cylindrical tube 75mm outer diameter and about 300mm long. A decent bit of wall thickness helps for stiffness but isn't critical. Home drainpipes are just around the right size if you can get some. I didn't want to spend the money so had to use a toy plastic tube which I had to thicken up with several layers of newspaper and glue plastered on. I also mixed some black paint into the glue to save some painting effort later.

Everything is then built onto this barrel, starting at the front. Cut out a suitable sized piece of foam and hot glue it around the barrel to build up the shape. I used an old exercise mat about 8mm thick which was easy to cut with a scalpel but also meant it damaged easily and deforms if in contact with the glue gun nozzle, so be careful! Shaping the front piece of foam is done carefully with a scalpel, it'll get tidied up later.
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6 comments
Jun 7, 2011. 10:19 AMrashie123 says:
Awesome!!!!!
Dec 1, 2009. 8:47 PMxXnocturnusXx says:
wait...so the end of the barrel is foam?...thats kinda lame, would it be possible to harden it by covering it with wood filler...or fiberglass resin (i have a lot of that)?
Dec 1, 2009. 9:34 PMxXnocturnusXx says:
never mind, im going to get a biger piece of pvc pipe and slide it over the front of the barrel in two diferent sections and sand the front one in a slope, to replace the foam at the front...
Sep 27, 2008. 6:54 PMpeach_fart says:
dude the barrel is oval shaped, hence the oval shaped portals
Nov 21, 2009. 8:29 PMREA says:
i have gmod and portal. its definitly round. try to prove me wrong.
Oct 1, 2008. 5:22 PMMarche says:
Open the source SDK and open the portal gun model in hlmv and come back. I'm pretty sure it's round because it would take extra work to make to make the cylinder the barrel it's based on an ovoid. But in the game code itself the portal is just a oval shaped render-target camera pointed to the other side and the border is just a sprite with some particles drawn around it. The shape does not rely on the model, If you are crafty enough you can switch out the portal gun model for the Half Life 2 Pistol and it wouldn't make a difference since Portal and Half Life 2 run on the same engine. In code the weapons are very flexible to avoid errors. I'm a bit of a Source Engine freak. I Practically live in the Source Engine's API.
Oct 3, 2008. 3:36 PMpeach_fart says:
i looked at a pepakura file ripped from the game and it was an oval. you can check the barrel with pepakura.
Oct 4, 2008. 10:17 AMMarche says:
http://i299.photobucket.com/albums/mm293/Marche96/untitled3.jpg
That is WAY better than converting it into a third party 3d program.
I don't own portal so could you take a screenshot of the barrel for me?
Dec 26, 2008. 9:18 AMpeach_fart says:
i saw my avatar in that pic.
Oct 2, 2008. 8:36 AMpoletovision says:
Why don't you just look at yourself in a portal? No one else has noticed the mirror effect you get when you put 2 portals right next to each other? You look face one, and just look at the other and it's a front image of yourself.
Dec 17, 2008. 6:31 PMDefault117 says:
There is a cheat code where you can put the portals on top of each other. It makes a mirror and you can see yourself (and the gun).
Dec 17, 2008. 6:35 PMDefault117 says:
If you listen to the commentaries they tell you why. It's because what you see in the portal is actually a virtual camera in the other one(yes I listened to them).
Dec 26, 2008. 9:19 AMpeach_fart says:
wtf?!?!? it happened again! i got someone elses comment in my email! whats going on?
Dec 27, 2008. 1:02 PMDefault117 says:
Eh?
Dec 27, 2008. 7:04 PMpeach_fart says:
comments people make to other people keep in popping up in my email its stupid.
Dec 28, 2008. 2:13 PMpeach_fart says:
i mean like someone called person replies to someone called someone i sometimes get that in my email.
Dec 28, 2008. 12:33 PMpeach_fart says:
27/11/08? theres more than 12 months in a year?
Dec 30, 2008. 12:45 PMDefault117 says:
Not everyone goes by the mm/dd/yy.
Dec 30, 2008. 12:59 PMpeach_fart says:
it was a joke.
Dec 30, 2008. 8:06 PMDefault117 says:
Oh...well...then...haha. Good one! :D
Dec 27, 2008. 10:36 PMDefault117 says:
Haha :P
Oct 7, 2008. 11:43 AMboegen2 says:
garys mod?! cant you spawn such thing in GM?!
Dec 30, 2008. 1:00 PMpeach_fart says:
yes. you can spawn props, entities, weapons and npcs in gmod.
Oct 2, 2008. 11:37 AMMarche says:
Yes, render target camera is basically a camera and monitor.. If you open up the Source SDK in steam then go to the model viewer you can look at the model up close like the modeling program used to create the model.
Oct 2, 2008. 11:45 AMMarche says:
Look at my above post. I'm just posting this so you get the email to look at it. I don't own portal but it's a hell of a lot more work to turn a cylinder into a oval type thing and have it make sense or look even. Valve wouldn't do anymore than what's necessary. in HL2 or Portal open up the console and chanve the cheats CVAR on with this: "sv_cheats 1" Then aim at the ground and type "prop_physics_create models/weapons/v_crossbow.mdl" And see the result.
Oct 3, 2008. 3:41 PMpeach_fart says:
its the crossbow that you hold. everything is there except the other side and your arms stop at your elbows. i looked at this in garrys mod by spawning in the hl or hl2 weapons folders. click on browse and look through.
Oct 4, 2008. 10:19 AMMarche says:
There is no point in making the engine render something you can't see. That's the main reason we don't have a Gordan Freeman model.
Dec 26, 2008. 9:21 AMpeach_fart says:
Gordan FREEman!
Oct 1, 2008. 4:59 PMbounty1012 says:
actually I think its round too. Its propably a ball of energy when it comes out and it spreads on the wall hence the oval shaped portals.
Oct 3, 2008. 3:38 PMpeach_fart says:
that would make circle portals
Oct 3, 2008. 8:48 PMbounty1012 says:
"...It spreads on the wall hence the oval shaped portals"
Oct 4, 2008. 12:20 AMpeach_fart says:
drip some water on paper and it will make a circle. and anyway, its just a game.
Dec 9, 2009. 3:15 PMXerillum says:
It's still a physics-based game, and real physics should be applicable to it.
Oct 4, 2008. 2:41 PMbounty1012 says:
I agree it is just a game I dont know why people camp out in front of best buy to buy these games... but If you drop water on a piece of paper it will shape itself like an oval after it spreads.
Oct 5, 2008. 11:11 AMMarche says:
I can make it into a dragon for all that matters. There is no restriction on shape in the code itself. They made it oval purposely
Mar 28, 2009. 5:14 PMdemonicgod says:
SHUT UP!!! GOD!

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Author:chiok(Chiok Li Designs)
Completed a masters in mechanical engineering and then realised I didn't want to be an engineer. So I'm a freelance propmaker and costumier for film, theatre and music videos. Occasionally, I need t...
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