# Thread: How do I draw an arc of specific length?

1. ## How do I draw an arc of specific length?

Try as I might I cant draw an arc of 1280mm in length around a circle having a radius of 350mm (the circle that is). Using the 'Start, Centre, Length' option only results in the message 'Invalid' when I put the length of 1280 in. I'm confused. Can anyone help. Thanks

RD

2. ## Re: How do I draw an arc of specific length?

If your start point is on the circle and the center of your arc is the center of the circle then it will not work. The length is cord length not the radial length when using SP Center, Length option. Seeing how the diameter (700) of the circle is less than the length (1280) it's graphically impossible to create.

3. ## Re: How do I draw an arc of specific length?

Try as I might I cant draw an arc of 1280mm in length around a circle having a radius of 350mm (the circle that is). Using the 'Start, Centre, Length' option only results in the message 'Invalid' when I put the length of 1280 in. I'm confused. Can anyone help. Thanks

RD
One way....draw a circle with the required radius, break out a portion to form an arc, use the lengthen command to set the Total length.

Originally Posted by JMurphy
Seeing how the diameter (700) of the circle is less than the length (1280) it's graphically impossible to create.
Hmmmm..... With a diameter of 700, the circumference of a circle would be ±2199, so a 1280 length arc is possible.....

4. ## Re: How do I draw an arc of specific length?

Originally Posted by rkmcswain
One way....draw a circle with the required radius, break out a portion to form an arc, use the lengthen command to set the Total length.

Hmmmm..... With a diameter of 700, the circumference of a circle would be ±2199, so a 1280 length arc is possible.....
The length is possible yes but the arc command with SP, CEN, LEN option the length uses the cord distance.
Command: _arc Specify start point of arc or [Center]:
Specify second point of arc or [Center/End]: _c Specify center point of arc:
Specify end point of arc or [Angle/chord Length]: _l Specify length of chord:

5. ## Re: How do I draw an arc of specific length?

Originally Posted by Jmurphy
The length is possible yes but the arc command with SP, CEN, LEN option the length uses the cord distance.
Command: _arc Specify start point of arc or [Center]:
Specify second point of arc or [Center/End]: _c Specify center point of arc:
Specify end point of arc or [Angle/chord Length]: _l Specify length of chord:

6. ## Re: How do I draw an arc of specific length?

Originally Posted by rkmcswain
One way....draw a circle with the required radius, break out a portion to form an arc, use the lengthen command to set the Total length.

Hmmmm..... With a diameter of 700, the circumference of a circle would be ±2199, so a 1280 length arc is possible.....

Thanks my friend. That worked perfectly. Problem solved.

Thanks for all the replies.

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