Help! I have four faces which are connected at 90 degree angles, forming a sort of corral. The sides of these faces are angled (at 71.3 degrees). I need to rotate each face inward so that the top corners are connected, but I just can’t figure out the angle needed. (I thought the obvious answer was 18.7 degrees; it’s close, but still not touching.)
I feel like there must be a simple method or mathematical formula to solve this, but I just can’t work it out. Hoping someone can offer advice!
//edit: obsolete varaints
I’d be inclined to do it differently from the beginning. I’d use a profile, a square path, and Follow Me.
There is an extension called Rake and Splay that is very useful for sorting out the correct angles for things like this but for a simple shape like yours, Follow Me would be faster and easier.
If you are really trying to sort out the angles, you can measure them off the resulting solid.
here is one way:
You need to have a true intersection on the ‘inner’ square. This can be done with the Pie tool, but you will need to have a plane in which to draw the pie…
First, create the inner square: I use the Tape measurement tool to creat guides.
Then hit the rectangle tool, hit the Up key for maintaining the blue plane, hit Ctrl for Centre start the rectangle.
Because it is constraint in the Blue plane, you can use the intersections of the guides:
Then, create the plane for the Pie and rotate one side to the intersection:
With the Pie tool, the lengt of the side will remain the same and you can get a true intersection on the edge of the inner square:
Note:
I have made a group of the sides
Platform.skp (205.1 KB)
Fun morning challenge coming up with new ways to tackle a problem, good for getting the little grey cells up and running 
. In addition to the excellent ways presented I have one leveraging intersect. If you had pro this would be a snap with solid tools but even with Make you can do this with intersect and the eraser tool (second video).
Though quick, the length of the side is not the same off course.
Maybe the OP can elaborate.
@MBGM-MBGM
Very true, the sides get elongated so perhaps that’s not so clever.
Great suggestions! I really like the ease of @DaveR , @endlessfix and @mihai.s 's (now deleted) ideas, but for this project the dimensions of my starting faces must remain accurate, and as the faces are rotated inward the height of the object should change. But although these methods won’t quite work here, these ideas will be very useful in future builds!
@MikeWayzovski 's method appears to retain the face’s dimensions, which is exactly what this project requires! (I also had an idea that I could create a triangle from the original face, and use the formula for a four-sided pyramid to calculate the center height, then determine the angle from the bottom of a face to the center height. I’m not sure if my idea would work, but it will be interesting to play with later.)
Thank you everyone for your great suggestions!
Follow Me won’t change the size of the sides. If you’ve drawn the profile correctly to begin with, it’ll be accurate after the Follow Me operation has completed.
I deleted my variants when I realized that the desired angle I could achieved by using a CAD software in which I could draw a real circle. Then I saw the version of @MikeWayzovski, and I did not add my new version, because his variant solve the problem directly in SketchUp with that Pie tool. 
Using DraftSight
What I meant to say was that as the top of the face is rotated inward to connect with the other faces, the height of the finished object (an angled base) becomes shorter than the original face standing straight at 90 degrees to the “floor.”
In your example, the face remains perpendicular to the floor, so as it follows the square, it remains at its maximum height. After the excess areas are deleted, the finished object is too tall, and the angled faces won’t have the same dimensions as the original face. (Perhaps later I can post a video demonstrating how the new face has different dimensions from the original)
They were still fun to watch, thanks! (I’m new to Sketchup, so all these ideas are exciting to me!)
Here you go, no guides, no boxes, just one edge, the pie tool and the inference system.
Sweet, pretty slick as usual Box! It must be said that Daves follow me works too if the slope/line is drawn to the right length to start.
Sorry @DaveR, I was wrong! I’m not seeing how it happens, so I’ll need to play with this method later. I see you emphasized if the profile is drawn correctly, are you referring to the shape of the face, or something else?
The profile is the shape that gets extruded with Follow Me. In this case I used half the cross section of the final shape.
Since the height of your sides are fixed, you need to draw the profile such that the sloped line matches that dimension.
No matter what method, the key is the Pie tool
It can’t hurt to have a piece of pie while doing this sort of thing.
Also very nice, thanks!
