Tangent line, selection of geometry to define tangency

david_cook325

When I try to add a tangent line to a pair of sketch lines at a corner, sometimes the tangent line is based off the correct line, sometimes it is not.  How do we determine which line a tangent line will align to when there are multiple choices?

david_cook325

John

You are still trying to instruct me on how to constrain lines and arcs that already exist.  I'm trying to use the 'Tangent arc' tool that creates an arc tangent to a selected line, except it does not allow you to select the line.  But now that I've gone through all trouble to cut and paste the notes of the button and read it, I realize that that the line itself only needs to be selected, I was waking up the line and then grabbing the end point expecting it to add the curve to the 'woken up' line.  So after more experimenting I see that the line has to be selected somewhere between the desired end point and the mid point of the line and you don't then select the point...

Thanks for trying to help on something I made more difficult than it needs to be :-)  

john_mcclary

Please post a screen shot, or specify which "lines" you mention above are actually arcs/circles.

Tangent only takes 2 selections at a time:
* arc & line
* arc & arc
* arc & spline

So your answer should be. Whichever 2 lines you selected, those will be tangent.

Edit:
You will need to add a new tangent for each line you want tangent.

david_cook325

John

This is for the instance that there are two lines already in a sketch that meet at a point, one could be a construction line and the other the line I want to add a tangent line to.  Then you turn on 'tangent arc' and select the point you want to sketch the tangent line from, in there case it can select either of two line.  Everytime I try this I can't get it to change which line it went from.

I attached a drawing and you can see that both tangent arcs are tangent to the construction lines and not the geometry line.  Is there a key to get tangent arcs to swap from available reference lines.

Another question, how do you attach screen shots in these forum posts without having to go through the trouble of saving a file.  I used windows-S to grab the screen shot but had to go open paint and save a file to get it into this message?

Thanks

john_mcclary

When you constrain tangents select lines and arcs rather than points.
In fact you cannot select points. It may look like it but you will just be clicking very close to the end point of a line

I color coded each mouse click below. which results in 3 (separate) tangent constraints.
If you select the constraint it will highlight what it is constrained to. (see lower image)

If you made a mistake by selecting the wrong line. You will need to delete the bad constraint and try again.

selecting the tangent button first.
Then clicking these 6 locations will result in:

Arc X is tangent to Line A
Arc Y is tangent to Line C
Arc Z is tangent to Line C



If you have two lines that overlap.
Say If underneath "line C", there was a short "line D" that you cannot select.
Then right click near where you think "line D" is, and choose "Select Other", then you can select the correct line in the menu.


I just use Windows snipping tool, then save and upload...

david_cook325

John

You are still trying to instruct me on how to constrain lines and arcs that already exist.  I'm trying to use the 'Tangent arc' tool that creates an arc tangent to a selected line, except it does not allow you to select the line.  But now that I've gone through all trouble to cut and paste the notes of the button and read it, I realize that that the line itself only needs to be selected, I was waking up the line and then grabbing the end point expecting it to add the curve to the 'woken up' line.  So after more experimenting I see that the line has to be selected somewhere between the desired end point and the mid point of the line and you don't then select the point...

Thanks for trying to help on something I made more difficult than it needs to be :-)  

john_mcclary

No problem. I'm glad you got it working