topic Re: Can anyone guide me to create an irregular shaped polygon in AutoCAD Forum

Can anyone guide me to create an irregular shaped polygon

Anonymous — Thu, 20 Aug 2020 10:47:46 GMT

Hi! I have an irregular shaped plot and I'm having trouble drawing it in AutoCAD. Most of the videos on Youtube are only of 4 sided polygons but this is really different. Would appreciate the help.

Thanks!

Re: Can anyone guide me to create an irregular shaped polygon

vinodkl — Thu, 20 Aug 2020 11:11:36 GMT

Hi,

If you know the measurements of the sides along with the angle then you can draw any shape in AutoCAD. Use the command "POLYLINE" to draw. You can also use the command "ATTACH" to attach the image of the floor into the AutoCAD and "SCALE" the image with "reference" using one of the measurements and then trace over the image.

Re: Can anyone guide me to create an irregular shaped polygon

Kent1Cooper — Thu, 20 Aug 2020 12:13:31 GMT

To do that with any precision, you need not just the lengths of the edges, but some kind of information about angles, whether metes-and-bounds-type bearings, or angles of changes in direction between edges. Without that, there are an infinite number of solutions.

Re: Can anyone guide me to create an irregular shaped polygon

Anonymous — Thu, 20 Aug 2020 12:35:57 GMT

I know for sure that it can be drawn in AutoCAD using circles as I just saw on youtube that it can be done for a 4 sided shape, but i don't know how to do it for a 6 sided figure.

Re: Can anyone guide me to create an irregular shaped polygon

dbroad — Thu, 20 Aug 2020 12:54:38 GMT

To draw a hexagon, use the polygon command. To draw the shape pictured in your original post, you must know the angles as @Kent1Cooper stated. Is this in France? I tried to look up French surveying standards but was unsuccessful.

Re: Can anyone guide me to create an irregular shaped polygon

Anonymous — Thu, 20 Aug 2020 12:56:37 GMT

I don't know exactly as I just picked it up from the internet.

Re: Can anyone guide me to create an irregular shaped polygon

leeminardi — Thu, 20 Aug 2020 13:16:52 GMT

A 4 sided shape where all 4 lengths are known but none of the angles has an infinite number of possibilities as noted earlier. It can also be considered a 4-bar mechanism as shown here . A six sided shape where all the lengths are known would require 3 angles to be specified to fix its shape.

Grubler's equation can be used (except in special cases) to determine how many degrees of freedom exist. That is, how many angles must be known to fix its shape. The equation is:

3 * (L - 1) - 2 * J = DOF

For your 6 sided shape we have L = 6 (number of links) and J = 6 (number of joints)

3 * (6- 1) - 2 * 6 = 3