How can I draw a circle quad at Q and tan to the arc shown?


Best method wanted for :-

I need to draw a circle where the red line currently is (that was drawn start and end tan using curve tool)
I need it starting tan at Q and ending tan to the 1.5inch rad arc.
by starting tan at Q, that is same as its quad being at Q if its far side quad is on x axis from Q)

I need to find out what rad circle will fit there.
Only tool I see expects user to indicate the rad required.

circle tan and quad Q and tan to arc.3dm (127.2 KB)


Hi @Steve1
It’s fairly simple; here shown in V7, but I believe (or hope, rather) it’s the same in V5 :grimacing:

Just use the Arc command, invoke the Tangent option and make sure you Osnap to the endpoint of the vertical line of the rectangle, use FromFirstPoint and select the second point near the tangent of the large arc.

HTH, Jakob

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It is.

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Hi Many thanks,
it works, however I like to knw what I am doing… its not just the arc tool its selecting tangent when the first click is made and ‘from first point’ for the second, which I struggle to understand the significance of ‘from first point’ what that refers to as any curve occurs from the first point or does it mean tangent from first point, still puzzled.
Best to understand what its doing with those options.



No that isn’t necessarily so… For example if you do a line perpendicular from a curve the placement on the curve won’t honour the first pick unless you use FromFirstPoint.

In your example, using this option helps force the pick of the second point to be tangential to the arc and not tangential to the unwanted curve. If you don’t use it then you may struggle to avoid getting the curve tangent at the intersection point.