Just for fun - QCAD drawing challenge !!!

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Moderator: andrew

andrew
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Joined: Fri Mar 30, 2007 6:07 am

Re: Just for fun - QCAD drawing challenge !!!

Originally posted by husky:
This machine was one step in the production chain for cheese manufacturing and it purpose was to drain, pre-press and cut cheese.
Completely built out of Stainless steel, length 25' - 30', width approx. 8' and a height of approx. 15'.

slyde
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Location: Turnip City, Texas

Re: Just for fun - QCAD drawing challenge !!!

Mine's kind of off, but it was fun trying. Thanks for the challenge
Attachments
Masonry drawing challenge.dxf
Look! It's a bird. No! It's a plane! NO! It's QCAD hotkeys...faster than a possum falling out of a tree!!

OS: Linux Mint 18.3 Sylvia [64-bit]

Husky
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Re: Just for fun - QCAD drawing challenge !!!

Hi guys - somebody here who can untangle my brain ......

I need a accurat solution and I'm more in a guessing mode than in a knowing mode.

I need to put small circles around a bigger circle. The small circles have to touch each other - no gabs between them. I know the diameter of the small circles and how many have to be placed. I don't know the diameter of the big circle. How can I figure that out?

The result should look like this - but more accurate .....

Husky-2019.04.09-07.png (47.32 KiB) Viewed 551 times

Values:
Diameter small circle = 6.35
Quantity = 52
Big circle = ???

I've the feeling MS Excel etc. should be the solution to the problem but Google and co. showed me always ad the end of all results " ... not absolute accurate".
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lphilpot
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Re: Just for fun - QCAD drawing challenge !!!

So would this work...

Imagine a larger construction circle centered on the big circle that runs through the center of each small circle. You can calculate its circumference (c = 52 * 6.35) and therefore its diameter (d = c / pi). Then reduce the diameter by 6.35 to make it coincide with the inside of each small circle, instead of their centers. Shouldn't that be the circle you want?

Would that work? I'm just doing this in my head, as if it were a programming exercise (and I'm no mathemetician!).
Len
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QCAD Pro on Xubuntu Linux (usually)

andrew
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Joined: Fri Mar 30, 2007 6:07 am

Re: Just for fun - QCAD drawing challenge !!!

- Draw 2 rays with angle 360/n = 360/52.
- Each of these rays will be tangential to one of the small circles.
- Use Draw > Circle > 2 Points and Radius to draw one of the small circles with radius = 6.35/2.
- With a simple auxiliary line (red) you can now construct the large circle.
Screen Shot 2019-04-09 at 21.25.15.png (27.93 KiB) Viewed 549 times

Husky
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Location: USA

Re: Just for fun - QCAD drawing challenge !!!

@lphilpot
Thank you for the try - but that isn't accurate enough.

@Andrew
Seriously? That easy? My brain was boiling and I haven't seen the obvious thing to do. THANK you!
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lphilpot
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Re: Just for fun - QCAD drawing challenge !!!

Yeah, after I thought about it a bit more, I realized the construction "circle" in my method was actually a 52-sided polygon, not a circle at all.
Len
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QCAD Pro on Xubuntu Linux (usually)

Husky
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Re: Just for fun - QCAD drawing challenge !!!

lphilpot wrote:
Tue Apr 09, 2019 9:57 pm
Yeah, after I thought about it a bit more, I realized the construction "circle" in my method was actually a 52-sided polygon, not a circle at all.
Don't worry about that. I was there too.
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Panchdara
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Re: Just for fun - QCAD drawing challenge !!!

So embarrassed.... had to remove my incorrect attempt