SketchUp Challenge?

Dave Richards

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Would any of our SketchUp users be up for a challenge? This should be a simple one for you.



Two 48 in tall, 4 in. square posts with a 2x2 placed diagonally between them such that the pointy ends of the miters are exactly at the top and bottom of the posts. Nothing to it, right?:D

The diagonal must measure exactly 2 inches square in cross section.
 
I'm already stuck.
The rotate tool is letting me down. I'm trying to rotate a 2x2 down into position, but it is working off of the WRONG side of the 2x2, so I can't get the point end lined up with the top of the 4x4.
:dunno:
 
Art, have you considered drawing the diagonal piece in place?

I did, but that seemed to me to need a whole bunch of math to figure out the correct cross section.

Here
15nov-test.jpg
View attachment 15nov-test.skp

I tried a different approach. I drew a long horizontal 2x2 precisely straddling the halfway point.
Then I made marks to set the exact center, and I spun it in place.

I think this is probably still wrong... I did get the ends to line up with the top/bottom of the post, but it seemed a bit by accident, as I did not see any way to force them to "snap" into place.

(I did not continue the exercise to clean up the ends of the 2x2s. I figured that wasn't really the point, and I wanted to show how I did it.)
 
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yeah, nothing like zooming WAY in to find the small errors.

I'll probably keep thinking about this long after my lunch break is done. bad Art. bad bad.
But right now I'm not getting it.

I want to approach this like a woodworker: just lay the 2x2 on top of the two posts and draw the line, then maybe transfer it to a miter saw to make the cuts. Done.
To do that I want to draw a 2x2, select the rotate tool, and then select the face to pivot, and then select the face that is doing the lining up. Right now, SU only seems to let me do the first two. It makes me use the pivoting face as the one that is snapping to a point/line/face. grump grump grump.
 
Just saw this challenge. I usually draw the components, then tilt the appropriate part until I get it in place. I'm having a little trouble understanding how to align things to draw the diagonal in place.
 
I got ~52-49/64" for the overall length of the diagonal and mine is aligned perfectly top and bottom.

Anyone else giving this a try? I don't want to spoil the fun for anybody.
 
Mystery not solved. :D Measure the actual length not the diagonal length of the the diagonal. I used the Cut List plugin to measure the overall length of the component's bounding box.
 
I see.

So did you get your corners to line up correctly?

FWIW, the Rotate tool is doing what it does but it isn't what we need as you've found out. Laying things out so you can draw it in place isn't very straightforward. Maybe you could do it after a bit of math. So there must be a different way. Here's a hint for everyone. Maybe there was a tutorial done about this sort of thing which would give you a method that is easy. ;)
 
OK. This whole thing started today because I received an e-mail from a guy who was trying to do something similar on a table he's building. I'd been thinking about giving you guys a challenge now that summer is over and this seemed like a good one. As you figured out, this isn't quite as straightforward as it might seem at first. Even just laying this out is tricky and that has nothing to do with SketchUp. Think about trying to lay it out on paper. You'd have the same problem. Even doing it in wood you would offer up a longer diagonal and move it around until it fit, mark the angles and cut the piece.

There is an easy solution in SketchUp using a tool in the FredoScale plugin set. I wrote a blog post on this exact thing nearly a year ago. Check this out.

Thanks being good sports and humoring me. Maybe you'll find something else to use this for.
 
OK, so when I looked at my measurement again, it was the point-to-point diagonal length. When I draw a line perpendicular to one end of the diagonal to have a reference, I get the correct overall length of 52 49/64. Both of my points match the ends of the posts. I used the Rotate tool by anchoring the bottom edge of the diagonal and grabbing the top edge of an over-length 2x2 diagonal and pulling it down to the top of the second post. That's probably clear as mud.
 
Ah, I get the purpose of the exercise now. I just cheated. Using the rotate tool does not "step" to a position that aligns the ends of the diagonal perfectly. I rotated it close and then typed in a specific amount to get it to "nudge" into perfect alignment. Took 4 or 5 tries and this would be bothersome for doing any number of these with differing values of "tilt". "Making" it work for a one-off is no big deal but, for use on a project with varying angles, lengths, etc. a more elegant method would certainly be the better way to go. I use a few of Fredo's plug-ins. Thanks for showing me another. It worked great and took a fraction of the time.

sh chal-2.JPG . sh chal-3.JPG
 
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