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Drawing an arc tangent to a line?

Builder
Builder

In a sketch you can use the Profile tool to draw an arc that is tangent to a line pretty easily (using the arc quadrant).  However, if you have an existing line and  you just select the arc tool, the only options are "Arc by 3 points" and "Arc by center and end point".  There is no tangent arc option (at least not an obvious one). Is there a way to do this without having to explicitly apply a  tangent constraint?  Thanks.

9 REPLIES 9

Re: Drawn an arc tangent to a line?

Siemens Phenom Siemens Phenom
Siemens Phenom

Hi pmk3,

 

When in Sketch and with the Profile function activated - press F1 - it will activate the help document on specific subject /active feature. In the web brower window with the document that is activated excplore the information. For your specific subject click the "The arc quadrant with Profile" option in the menu to the right. It will provide explanation to your issue.

 

Best Regards

Fred

 

 

Re: Drawn an arc tangent to a line?

Builder
Builder

@Sandman wrote:

Hi pmk3,

 

When in Sketch and with the Profile function activated - press F1 - it will activate the help document on specific subject /active feature. In the web brower window with the document that is activated excplore the information. For your specific subject click the "The arc quadrant with Profile" option in the menu to the right. It will provide explanation to your issue.

 

Best Regards

Fred

 

 


Thanks for reply, but I already saw that in the help.  I understand how the arc quadrant works.  The problem is getting it to appear if you start with an existing line.  If you have an existing line, click the profile tool, switch to the arc tool, and click on the endpoint of the line, the only option is to create the arc using the 3 point method.  If you use the Profile tool to create the line first, then sure, the arc quandrant will appear and you can create tangent arcs all you want. But that's not what I'm trying to do. 

 

I'm very surprised NX doesn't have a dedicated tool for doing this, like virtually every other CAD package out there. I'm hoping there's some trick I'm missing.

Re: Drawing an arc tangent to a line?

Siemens Phenom Siemens Phenom
Siemens Phenom

Hi pmk3,

 

For your specific issue use the 3-point arc where you first select the 2 end points does not matter if you draw your arc from the endpoint of your line or the oposite. Move your cursor around the endpoint of the line until you see the quadrant tool. Ensure to have the "Create Infered Constrainst" activated else the curve will only be created tangetly but no actual tangency constrain created or maintained when the skecth is modified. I should add that this behaviour is default weather your using the 3-Point Arc while re entering the Sketch Profile Tool. 

 

Best Regards

Fred

Re: Drawing an arc tangent to a line?

Phenom
Phenom
  1. Start Profile sketch
  2. Click an endpoint of the existing line.
  3. Then while depressing LMB drag the curser to the end location of the arc and click.
  4. Just move the mouse around and it will simulate possible arc depending on the mouse location. Click when it gives tangent constraint; the way you want.

Refer the video attached.

(view in My Videos)

Michael Fernando


Die Designer
NX 11.0.2.7 + PDW

Re: Drawing an arc tangent to a line?

Phenom
Phenom

I personally prefer to create tangent constraints manually, and sometimes turn off the inferred constraint creation for tangents. When there are many circles and arcs in the sketch, in can be too easy to create an inferred tangent constraint by mistake. If I don't notice that this happened, it can become confusing to trouble-shoot the sketch when it becomes overconstrained. 

 

I also am very cautious of mid-point constraints. It is easy to inadvertantly create these constraints.

Re: Drawing an arc tangent to a line?

Builder
Builder

Thanks for the additional replies. I realized shortly after my second post what everyone suggested, that I can create a tangent arc simply by using the inferred tangent constraint.  One of the banes of coming from another CAD system (SE in my case) is the programming locked in your brain of how certain operations should be done. Smiley Frustrated  Using the inferred constraint works just fine.  It just wasn't on my radar!

 

Thanks for the help.  

Re: Drawing an arc tangent to a line?

Siemens Phenom Siemens Phenom
Siemens Phenom

pmk3,

 

As MarkLawry points out it is sometimes good to create the curve segments without the constraints and add them later manually - if so there is no need to turn off the "Create Infered Constraints". By pressing the "Alt" key you temporary (while pressing the "Alt" key) disable the creation of infered constraints. This means that for the enteties where you want to add a specific constraint maybe not nessecary provided you can add them manually to ensure the correct behaviour of your sketch. Just a small tip.

 

Best Regards

Fred

Re: Drawing an arc tangent to a line?

Builder
Builder

@Sandman wrote:

pmk3,

 

As MarkLawry points out it is sometimes good to create the curve segments without the constraints and add them later manually - if so there is no need to turn off the "Create Infered Constraints". By pressing the "Alt" key you temporary (while pressing the "Alt" key) disable the creation of infered constraints. This means that for the enteties where you want to add a specific constraint maybe not nessecary provided you can add them manually to ensure the correct behaviour of your sketch. Just a small tip.

 

Best Regards

Fred


Thanks for the tip Fred. Good to know!

 

On last comment I wanted to make on this is that even though you can draw a tangent arc using the 3 point arc tool  and inferred tangent constraint, it's still not as good as having a dedicated tool. The reason being is the dedicated tool can do this in two clicks, whereas the 3 point arc tool requires 3.  So there still is an argument to be made for adding this.

Re: Drawing an arc tangent to a line?

Phenom
Phenom

It depends on what you are doing.

If you want to create a fillet in a corner, it is quicker to sketch the theoretical shape, and then add the fillet with two clicks. 

 

Using Selection Intent Options such as Follow Fillet or select Region Boundary Curves, you don't need to trim the corner.