Drafting Techniques

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rubberducky9o9
Posts: 4
Registered: ‎09-27-2012
Message 1 of 7 (543 Views)

varying radius arc

543 Views, 6 Replies
09-27-2012 05:07 PM

An arc can be defined as a part of a circle i guess. Meaning there is a constant radius. But is there a way to make a  varying radius? 

imagine an arc starting at 90 degrees north and coming down to the right ending at 0 degrees east. The radius from the center to the top is 1 and the radius from the center to the east point is .5

keep in mind i would like the arc to be completely tangent to the 90 angle we made. 

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GrantsPirate
Posts: 1,604
Registered: ‎08-15-2008
Message 2 of 7 (531 Views)

Re: varying radius arc

09-28-2012 06:51 AM in reply to: rubberducky9o9

Use the ellipse command and trim the parts you don't need.  You won't be able to specify a radius.

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JGerth
Posts: 2,117
Registered: ‎12-05-2005
Message 3 of 7 (503 Views)

Re: varying radius arc

10-02-2012 10:48 AM in reply to: rubberducky9o9

I agree with the ellipse, but it's certaqinly feasible to specify the two radii..

 

Command: ellipse

Specify axis endpoint of ellipse or [Arc/Center]: c

Specify center of ellipse:
Specify endpoint of axis: @0.5<0

Specify distance to other axis or [Rotation]: @1<90

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troma
Posts: 2,520
Registered: ‎05-21-2008
Message 4 of 7 (413 Views)

Re: varying radius arc

11-27-2012 12:52 PM in reply to: JGerth

I think what is needed is a spiral, not a quadrant of an elipse.  Unless possibly these are geometrically identical objects.


Credit where credit is due! Give kudos or accept as solution whenever you can.

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stevor
Posts: 853
Registered: ‎12-26-2005
Message 5 of 7 (358 Views)

Re: varying radius arc

01-09-2013 05:57 AM in reply to: troma

That can be a SPLINE. You can make your appropriate ARCs at each end, then superimpose a SPLINE  to fit as well as you can.

 

Other methods would include an arbitrary number of  tangential ARCs, posibly  by the  BiArc  method.

S
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Kent1Cooper
Posts: 5,500
Registered: ‎09-13-2004
Message 6 of 7 (225 Views)

Re: varying radius arc

03-27-2013 01:51 PM in reply to: rubberducky9o9

rubberducky9o9 wrote:

An arc can be defined as a part of a circle i guess. Meaning there is a constant radius. But is there a way to make a  varying radius? 

imagine an arc starting at 90 degrees north and coming down to the right ending at 0 degrees east. The radius from the center to the top is 1 and the radius from the center to the east point is .5

keep in mind i would like the arc to be completely tangent to the 90 angle we made. 


Yes, an Ellipse is really what you want if you need it to be tangent to right-angle directions at both ends.  And yes, you can specify the two radii, and you can draw it as an elliptical arc directly, rather than draw a full ellipse and trim it.  Use the Ellipse command, choose the Arc option, then the Center option and give it the center point, then aim the cursor in an axial direction [easiest with Ortho on] and type in the one radius, aim the cursor in the perpendicular direction and type in the other radius, and then pick the starting and ending directions to define the ends of the elliptical arc.

Kent Cooper
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Bob_Zurunkle
Posts: 1,040
Registered: ‎03-24-2011
Message 7 of 7 (213 Views)

Re: varying radius arc

03-28-2013 08:51 AM in reply to: Kent1Cooper

You could create 2 circles, one at each radius, with their quadrants in the desired locations. What would remain to do would be a 3rd circle that is tangent to both of the other circles. However, you'd need a radius, or you could "wing it". The final step would be to trim away everything that doesn't look like your desired result!

If by some odd chance my nattering was useful -- that's great, glad to help. But if it actually solved your issue, then please mark my solution as accepted :smileyhappy:
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