Using Tangent Arc

wolfgangh

Hi,
I'm kind of new to Onshape, and I don't use CAD for business reasons, which means I'm not an expert at all
However, I'm struggling with the tangent arc command, which is not behaving the way I've seen it in other CAD programs.
This is what I want to archive: connect a tangent arc (to a line or another arc, doesn't matter), but be able to chose the direction of the arc.
e.g. drawing a vertical line, adding a tangent arc to the endpoint, but not the way Onshape suggest to do, instead the opposite way (concave if that makes sense).
Is there an easy way to do that?
Many thanks, Wolfgang

andrew_troup

Wolfgang

The tangent arc tool does work in the way you want it to: you can concatenate arcs, maintain tangency, and still reverse the direction of curvature simply by moving the mouse.

You might need to do a hard reload of the browser tab (Shift + Refresh) to dump and reload the cache: sometimes functionality is lost during a session, and this usually restores it

nav

Hi @wolfgangh I remember trying to use the tangent arc tool earlier when I wrote my post and didn't behaved as expected, I use chrome, but opened OS in Safari and it behaved as stated by @andrew_troup, went back to chrome Reloaded the browser and now is fully working as intended, you can concatenate arcs, and change direction with the mouse, thanks @andrew_troup .

Narayan_K

nav 's video.only the think is it is not showing tangent symbol while creating the arc because created arc is always tangent....you can see the tangent symbol by enabling "show constrain"  

  

peter_hall

@wolfgangh
Hi just keep finger on the mouse don't let go as this will finish command. Move mouse to left or right and the arc should invert to other direction. Then when happy don't forget to check menu and leave the tangent arc line!

wolfgangh

Hi Peter,
thanks for the quick answer. Unfortunately, this is not exactly what I'm looking for. I do know how to use tangent arc in general, but what do I have to do to get the bowing in the opposite direction (sorry, I'm not a native speaker, it may not translate very well)?
If I draw a line from bottom to top, and I want to add a tangent arc from the top end of the line, I can get that to the left or the right, but always having the bow facing upwards. I do want to have a bow facing downwards (hollow?)
Hope this explains it a little better.
Thx, Wolfgang

Narayan_K

Hi, Please find the below Giff image,

wolfgangh

@Narayan_K

thanks, this shows how it works with 3 point arc, and I'm able to do that as well. But what about the tangent arc (drop down the 3 point arc menu)?
In Alibre, I can chose the direction by moving the mouse. Can't get this working in Onshape (and I bet, it's a stupid user error )
Thx, Wolfgang

nav

Hi @wolfgangh the solution shown by @Narayan_K using the 3 point arc if I understand you correctly solves your issue, as you can see in his Video the tangent constraint gets activated when he moves up/down the arc, meaning is a tangent arc. 

wolfgangh

Hi @nav, the solution @Narayan_K has shown works for some sketches, but not for all. I know there is always a way to get things done, but it could be an easy or more complicated step. At the moment, I'm still learning how Onshape works, and I'm comparing how I'm able to archive things.
If you look at the picture below, the previously mentioned method with 3 point arc is not really helpful. You can still sketch this with some construction lines and diameters as I've done, but using the tangent arc would allow you to concatenate tangents, set radius and angle to get the same result bit easier (if you look at the R8 tangent, than R22 (20.01 degrees) and than R15 (20.07 degrees) etc.

Pic:


But as said earlier. I'm actually treeing to understand the differences and how Onshape works. So thanks for all of your replies!

Thx, Wolfgang

andrew_troup

Wolfgang

The tangent arc tool does work in the way you want it to: you can concatenate arcs, maintain tangency, and still reverse the direction of curvature simply by moving the mouse.

You might need to do a hard reload of the browser tab (Shift + Refresh) to dump and reload the cache: sometimes functionality is lost during a session, and this usually restores it

nav

Hi @wolfgangh I remember trying to use the tangent arc tool earlier when I wrote my post and didn't behaved as expected, I use chrome, but opened OS in Safari and it behaved as stated by @andrew_troup, went back to chrome Reloaded the browser and now is fully working as intended, you can concatenate arcs, and change direction with the mouse, thanks @andrew_troup .

Narayan_K

nav 's video.only the think is it is not showing tangent symbol while creating the arc because created arc is always tangent....you can see the tangent symbol by enabling "show constrain"  

  

wolfgangh

Hi,
thanks to @andrew_troup, @nav and @Narayan_K ! 
I'm now able to use the tangent arc. It was most likely not just a simple reload problem as stated in the answers above, but also a situation in my sketch. If you look at the R22 tangent starting from the R8 tangent, you notice a construction line coincident to the R8 tangent. as long as this line exists, I can't use the tangent arc in a way I'd like, but after deleting the line, I can immediately use it as demoed in the animations above.
So again, thanks to all for helping!