I made the structure below eventually meant to be an outdoor fireplace. I started by laying out two hexagons and a square and trying to pivot along their joining sides. This didnt work well, because afaict, there’s there no great way to rotate two things at once with the same angle, so it was a terrible guess and check game that left gaps. Is there a better way to create this structure?
I expect with a little searching on the net you can find the angles you’d need to use to rotate copies of the faces into place. I wouldn’t do that myself. Instead I would lay out the shape starting with an octagon and a square. Rotate/Copy the square around the center of the octagon. (Starting the octagon so it is centered on the origin would make this easier.)
Then use the Line tool to complete the hexagons.
I wasn’t too concerned about dimensions here but you can make it so the hexagons are regular along with the squares.
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wow, thank you so much. I’m not sure I would have worked that out myself.
How did you know what size to make the squares and hexagons, and how to space the two squares?
You’re welcome.
I expect you’d have hit on it soon enough.
I kind of just pulled numbers out of the air. I decided on a 5 in. square and started with a hexagon that is 5 in. on a side. I just drew in edges between corners to make the hexagons. As I said, they aren’t regular, though. That is, the edges aren’t all the same length.
If you want to make the edges of the hexagons the same, you need to adjust the position of the squares. I did that by putting a guideline at 45° through the origin using the yellow Protractor tool. Then I used the Tape Measure tool to pull parallel guidelines at 2.5 in. You really only need one, say the one closest to the green axis. Next I moved the square out on the green axis until the corner intersected the guideline. After that, using Rotate/Copy to make the rest of them put them in the right location.
After that a little drawing with the Line tool and you’re good.
If you draw a line through the midpoints of the faces of a cube so that you basically split it on the diagonal, you get the parts you need to make the shape.
I have posted it here as a gif several times but as I’m on a dying phone I can’t link any.
I had a go in a completely different way - as usual, though, @DaveR gets the prize for elegance and simplicity just using native tools.
I first experimented making a hexagonal component, then making a square component with the same length sides, all on the ground plane. Centred the square on the origin using the move tool and edge midpoints.
Then I registered one side of the hexagon on the square, and rotated a copy by 90°.
Made the two hexagons into one component, opened it for editing, opened one hexagon inside it for editing, then selected the whole hexagon (face and six edges) and rotated it up until it met its companion doing the same thing. I hoped I could get an exact inference when the two met, but alas not. But I got close - angle approximately 54.7° - but not an exact match. Tried increasing angular precision to 3 decimals, and experiment to get the corner to close - couldn’t do it!
Then I tried a completely different way. Found that someone had drawn in OBJ format a truncated octahedron (which is what this shape is called), found a free trial of Simlab OBJ importer plugin, and imported the OBJ file into SU.
That got me the shape, but with fully triangulated faces. Deleted the extra lines, made the hexagons and squares into components, then made two halves of the shape into a bigger component, mirrored the top and bottom halves with a 90° rotation, and got the full solid.
Then scaled it with the tape measure tool to make it have 10" sides, and measured the angle of slope of a bottom hexagon to the ground plane - measured as 54.736° using the Angular Dimension 2 plugin from Sketchucation plugin store.
Here’s the result. Truncated octahedron.skp (48.3 KB)
Image, with styles showing edges coloured by axis:
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Very roundabout, but gave me a bit of fun exercise for an hour or so.
But the result, measuring the angle of 54.736 degrees, means it would now be simple to draw with one square and one hexagon - just raise the hexagon by that angle, rotate four times, draw two squares in the gaps, mirror, then rotate one half and position it to make the whole.
And using the PipeAlongPath plugin, with 1" tubes created along the edges of the hexagons, and hiding all the square and hex faces, you could make one in tubing.
@john_mcclenahan thanks for the skp.
@DaveR I meant to say that i wouldnt have been able to work that out myself, heh. I spent about an hour with your technique and i just got lost in tape measures and protractors and continuously adjusting the squares that I’ve still not been able to get quite right. =/
I recorded a video showing the process but Box has added his version so I scrapped mine.
Found a computer.
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