Circle Through Three Points

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adze_cnc
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Circle Through Three Points

Post by adze_cnc »

 
A quick gadget. One of the more useful circle drawing commands in Rhinoceros 3D is "Circle > 3Point" which draws a circle through any three selected points (that are not co-linear).

This gadget simulates that command. It would be nice if the gadget interface had access to point selection in real time. But...
  1. you will need to create three objects (small circles work well) whose centres are the three points to create a circle through (see left side of image):
     
    circle-through-three-points.png
     
  2. then select all three "points"
  3. then select "Circle from 3 Points" from the gadget menu.
While I suggest using circles any three vector-based objects will work (see right side of image). Note the letter "C" was a text object converted to curves. The program will find the centre of the bounding box (the smallest rectangle) surrounding each of the selected objects and use those as the “points”.

Installation Instructions

Because the forum software doesn't allow attachments with ".vgadget" extension the file is uploaded as "Circle_from_3_Points.zip". Installation instructions are the same for both a new installation or in upgrading a previous version:

Instructions for Aspire and VCarve Pro versions v9. and above:
  1. download the gadget attached below as: Circle_from_3_Points.zip
  2. rename it to: Circle_from_3_Points.vgadget
  3. in Cut2D Pro, Vectric Pro, or Aspire click on then menu option: Gadgets -> Install Gadget
  4. navigate to where the downloaded and renamed file is
  5. select it and click Ok.
VCarve/Aspire should give you a pop-up saying the gadget was installed and you should see "Circle_from_3_Points" in the Gadgets menu.

Note: after downloading the ZIP file do not etract it but continue on to the rename operation (unless you are running Aspire v4.5 or VCarve v8. or lower in which you need to manually unzip and move the folder to where your gadgets are stored).

This gadget has been tested to work in VCarve Pro versions 7 to 11. I have not tried it in VCarve version 10.x or Aspire version 4.5 and versions 9 to 11 but it should work fine in those as it is using nothing version specific (such as tool selection).

Note: The default for Microsoft Windows is to hide etension of "known" file types. This means that you may be renaming "Circle_from_3_Points.zip" to "Circle_from_3_Points.vgadget.zip" without knowing it.

In the Windows Eplorer there is a View tab (probably) and under that is an option to show file etensions:
 
no hide file extensions.png
 
Attachments
Circle_from_3_Points.zip
(2.61 KiB) Downloaded 14 times

Jimcad
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Re: Circle Through Three Points

Post by Jimcad »

Thank you. I just installed it.
I may even get time to use it. :D

Jim

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sharkcutup
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Re: Circle Through Three Points

Post by sharkcutup »

COOL!!! :)

Sharkcutup
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adze_cnc
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Location: Vancouver, BC, Canada

Re: Circle Through Three Points

Post by adze_cnc »

You can do a 3 point circle manually. Just erect two perpendicular bisectors on a line between any two pairs of the 3 points [p, q, r] such as pq and qr. Where those bisectors meet is the circle centre and the radius is the distance between that and any point [p, q, or r].,
 
Highlighted intersection between two perpendicular bisectors is circle centre
Highlighted intersection between two perpendicular bisectors is circle centre
 
Attachments
manual-3pts.crv
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