## Tangential

Moderator: andrew

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Panchdara
Full Member
Posts: 74
Joined: Wed Nov 25, 2015 4:15 pm

### Tangential

Using 3.22.0.5 - can someone give me a lesson on using the Tangential tool? I just seem to fall flat on my face when attempting to use it.

Best
Tangential.jpg (35.88 KiB) Viewed 757 times

Husky
Moderator/Drawing Help/Testing
Posts: 2578
Joined: Wed May 11, 2011 9:25 am
Location: USA

### Re: Tangential

That will be a very short lesson .....
The tool is meant to draw a line - landing tangential on an arc, circle or ellipse.

Start point - where ever you need it.
End point will snap tangency on an arc, circle or ellipse.
Work smart, not hard: QCad Pro

Panchdara
Full Member
Posts: 74
Joined: Wed Nov 25, 2015 4:15 pm

### Re: Tangential

Thanks. But I still think there is a bug. I want to draw a line tangential to a circle. Say, 45deg. I draw the circle then choose the angular line (choose middle) and try and make it tangential to that circle - complete fail.

andrew
Posts: 6246
Joined: Fri Mar 30, 2007 6:07 am

### Re: Tangential

Panchdara: I can see that this is tempting, but the tangential snap tool does not work this way (and is not designed to work this way).

The only situation where this snap is useful is for drawing a line from a point tangential to a circle:
- Draw > Line > Line from 2 Points
- Click start point of line
- Click Tangential snap (as indicated in your screenshot)
- Click circle or arc

The tangential snap snaps to the tangent point of an imaginary line from the relative zero point (small red circle with cross) to the clicked arc. For all other situations, use the specialized tangent drawing tools or auxiliary constructions.

The reason behind this behavior is that snap functions are unaware of the tool you are using and are designed to work consistently across all tools. A snap function does not know that you are about to create a line with a given angle nor is it aware of that particular angle.

Panchdara
Full Member
Posts: 74
Joined: Wed Nov 25, 2015 4:15 pm

### Re: Tangential

Thanks Andrew. It's just that the tangential tool is available when in angular line mode. That seems to have messed me up. Also, sometimes I see "tangential" as a snap point sometimes - when, I can't seem to replicate. So, for me to make a tangential angular line to a circle, I first create the circle, then draw an arbitrary line at the given angle. Then create a perpendicular line to that angular line and then move that created perpendicular line to the center of the circle and redraw the same angular line at the intersection of the circle and perpendicular line - is that correct? I'm so dazed and confused. But a great learning experience - thanks to Husky and his 52 circles

J-J
Moderator
Posts: 409
Joined: Tue Mar 24, 2009 9:48 pm

### Re: Tangential

You can use orthogonal trough point, point being the center of your circle. you may then move your arbitrary line to the intersection of your perpendicular and circle
JJ

Panchdara
Full Member
Posts: 74
Joined: Wed Nov 25, 2015 4:15 pm

### Re: Tangential

Thank you JJ. That works a treat also... such a simple solution that I feel a little embarrassed to have had a brain f@rt.

Best
Hugh