Note: I only have access to the student version of Autodesk Inventor on this computer at the moment, so that is what I will be using to demonstrate this process and write out the steps, but Since I made it in 123D aswell, I will be posting both the Inventor files and Autodesk 123D files at the end of this Instructable.
The purpose of this Instructable is to provide a way for people to Create, 3D Print and/or Machine a version of the Turret from Portal 2 that will be incorporated with mechanical parts to redesign how the original Turret from Portal 2 works, while teaching them how to design objects, and use the software. The turret itself is not copyright protected, but all of the credit for it's original design, and my inspiration for making this goes to Valve.
I have had a desire to make one of these undeniably adorable, military grade turrets since I've played Portal 2 a couple years ago. And since then I've gotten some experience with Autodesk design software and now have the ability to continue on with this project. After about four days of drawing, redrawing; modeling and remodeling it(since there are no real references referring to the measurements of the turret), I have obtained a satisfactory result, while keeping in mind that I would eventually be printing it out and incorporating the mechanical workings I have made to replicate the actions of an actual turret from the game. You are welcome to redesign the mechanics I have created(on a limited budget), which I will be posting in a later Instructable. But for now, here are the step by step instructions to getting the shell, arms, and gun box ready for 3D printing, and assembly .
Step 1: Video Instructions.
Note:Please watch in 720P or higher, or you won't be able to see the small numbers
Important Note: To do step 6(making the indention down the body) correctly in Autodesk 123D, simply extrude out the .2 inch gap, create a sketch on that surface, and offset the outline of the sketch .2 inches in, and fill in any gaps. Also when making the main body in 123D, you can just take an elliptical shape and stretch/distort it using the measurements provided in the video/instructions
Please excuse the lack of editing. I have no real video editing software on this computer
Also, Since I am more comfortable using Autodesk Inventor, that is what I will be using to do this "speed-modeling" here. You can take the basic concepts shown and apply it to Autodesk 123D.
Step 2: The Basic Shape of the Turret
In this Instructable, We'll be going over how to use the Polyline/line tool, ellipse/circle tool, trim tool, extrude tool, loft tool, and chamfer tool in Autodesk 123D/Inventor.
The first thing to do is to figure how to begin going about creating the basic shape. What I have found is that it is simply 3 ovals that overlap each other on the 3 dimensional plains.
First, Go ahead and make a Sketch on the XZ Plane and make a line that is 4 inches long starting at the center point, and going along the X axis. Then another line, starting from the center, that is 5.2 inches long, and going long the Z axis. Select the ellipse tool and click the center point, then the end point of the first line, and then the end point of the second, and finish the sketch.
Create a second sketch on the XY Plane and make a line on the X axis from the center that is 4 inches long, and then another line from the center along the Y axis that is 11 inches long. Create an ellipse using those 3 points, and then get the trimmer tool and snip off the left half of the ellipse and finish the sketch. (you may need to place a point at either end of the ellipse so the trimmer tool knows the limits of the trim)
Repeat the steps in the following paragraph above, but this time trim off the right half of the ellipse.
Now create a sketch on the YZ Plane and use the previous two sketches to make an ellipse that intersects both of the previous ellipses. Then, again, trim off the left half.
Repeat the steps in the following paragraph above, but this time trim off the right half of the ellipse.
Go back through each sketch and delete any STRAIGHT LINES. (they may interfere with lofting later on)
Place two workpoints on the top and bottom of where the two longer ellipses intersect.
Select the loft tool and select the top workpoint as the first selection. Then select the ellipse that is going across the XZ axis as the second. and then finally the bottom workpoint as the third selection. Go to the rail selection box and select each of the for semi-ellipses we made earlier and press finish loft.
We have now made the structure which we will base the body and arms of the turret off of.
Step 3: Making the Eye Hole for the Turret
Step 4: Separating the Body From the Arms
From the center, make a 2.4 inch line going across the X axis, and then a 6.5 long line, from the center, going along the Y axis. Then make an ellipse using the three points.
Next Make a line going along the y axis 4.615 inches upward. and then another line 1.690 inches long connected to the one we just made and running to the left, parallel to the x axis. The end point of that line should connect to the small ellipse we just made. From that endpoint, make a 70 degree line(or 110 degree's measuring from the right side) that extends past the main body(it doesn't really matter how long).
Then make a line starting from the center and going down the Y-axis that is 5.681 inches long. Make another line going off of that one, parallel to the X-axis and running left that is 1.167 inches long. Again, it should intercept with the ellipse we drew. Make a line off of that endpoint that is 260 degrees(with 0 starting on the right of the X Axis and running counter clockwise)(or 100 degrees as shown in the picture above) and extends past the main body. Again, it doesn't matter how long.
Now connect the two lines we made that extend past the body, but don't let the connecting line(s) intersect with the body itself.
Then select the mirror tool, and select the two lines that extend past the body, and it's connecting line(s) as the lines we want to mirror, and use one of the lines that run along the Y axis as the mirror line and click done.
Delete the lines that we used to mark the placement of the angled lines and the lines that we used to create the ellipse, so they do not get in the way later.
Use the trimming tool to trim the very top of the small ellipse, you should begin to see the shape of the Turret at this point.
Use lines to connect the mirrored lines we just created to their respective mirror. Do not let any lines pass through the main body.
Now finish the sketch and select the extrude tool and select the two arms that we made in the sketch. extrude these arms out of the body, and you should end up with a shape like the one in the picture above.
Step 5: Creating the Arms
Step 6: Making the Indention Down the Body
The only exception to this is the bottom line and the back face of the eye hole, those line should follow the original. Because if you think about it, a turret is not indented along the bottom surface.
Finish the sketch and extrude it .2 inches so it connects with the other half of the Turret.
Step 7: Making the Slit in the Arms.
Step 8: Shelling & Tweaking.
Step 9: Gun Box Time.
Now it get's a bit more tricky here, because we have to make a shape that fits perfectly into the arms, and fits the size constraints of the body. first we'll need to get the basic shape for it done. so create a sketch on the XY Plane. Since the thickness of the arm is .3 inches, we can figure out the contours of the inner arm by subtracting .3 inches from both dimensions of the ellipse.
So, starting from the center, make a line across the Y Axis 11 minus .3 inches long and a line across the X Axis 4 minus .3 inches long.
Create the ellipse, and then trim off the left half. Then create a new sketch an trim off the right half.
Now we will need two sketches that will constrain the shape on the YZ Plane when we loft it. To do this, make a line along the Z Axis that is 5.2 minus .3 inches long from the center. and then make another line along the Y axis that is 11 minus .3 inches long from the center.
Create the ellipse and trim off the left side. Then create a new sketch, remake the ellipse and trim off the right side this time
Now we need it to be able to fit inside of the XZ Plane of the arm, this will be one of the base sketches for the loft. To do this, create a new sketch on the XZ Plane. Again, we will be making an ellipse that will fit inside of the arm, and since the thickness of it is .3, we will be subtracting that from the original ellipse we made on the XZ Plane. so, along the Z Axis,from the center, make a line that is 5.2 minus .3 inches long. and on the X Axis, from the center, make a line that is 4 minus .3 inches long. Create the ellipse, but since this will be a base sketch, do not trim anything.
Now go back through and delete any STRAIGHT LINES in the sketches so they do not interfere with the loft.
Create two 3D Workpoints, one on the top, and bottom, where the ellipses intersect. These will be used as the other two base sketches for the loft.
Now select the loft command and click the top workpoint, then the ellipse on the XZ Axis that we made earlier, then the bottom workpoint. then select the four semi-ellipses that we made as rails for the loft and click finish.
Now, to make it fit inside of the rest of the arm, Remember the smaller ellipse we made to extrude the arm and body in the first place? Recreate that on a new sketch on the XY Plane. Finish the sketch and extrude(cut) it out of the entire shape. you should now have an elliptical shape with an oval cut out of the middle.
Now we need to figure out how long we want the gun box to be, I made mine 6.6 inches long for practical reasons, since these pieces will be used to make a working model later on. So Create a new sketch on the XY Plane and make a 3.3 inch line that runs along the Y Axis on EACH side of the X Axis. Now use that line as a reference to make rectangles above and below the line that are wider than the elliptical shape. When you extrude(cut) out these rectangles, you should just be left with a 6.6 inch slice of the ellipse in the center. There will be two gun boxes(one on the left and one on the right) just extrude one of them out so you are left with one.
We now have a shape that fits pretty snugly inside the general shape of the arm. In the next step I will go over how to build upon this shape so it actually looks like a gun box.
Step 10: Making the "Box" Part of the Gun Box
But I will explain the basic idea:
Simply extrude a rectangle off of the base shape we just made. After that give it detail and a way to connect with the main body, and then a way to connect with the arm. You can see examples of this in the files I'll be providing.
Step 11: The Eye
Step 12: The Leg Guards
I decided to model those pieces just in case this project places in the 123D contest so that they could be printed out. Below are my versions of the turret leg guards(trust me, there are many other versions)
Tell me in the comments if you think I should change something on them(and no, there is no way to have them accurate and have it able to fold up like in the Aperture Investment video.)
Step 13: Theoretical Mechanics for the Arms
(123D files will be uploaded shortly)
Step 14: Getting It Ready for 3D Printing
Note: If you want, you can make extrusions so you can screw the cut up pieces together after they have been printed
Note: The files may be edited so that the body can house extra parts. Any editing will be finalized by the end date of the 123D competition. (the mechanics themselves may also change as I substitute parts from the original plans. So the tolerances in the 3D files may vary up to the final contest date as well.)