12 Replies Latest reply on Jul 27, 2018 3:53 PM by Kyle Struck

# Line perpendicular to arc

Ok, I must be having a brain fart.

I have an arc and want to sketch a rectangle that will be perpendicular to the arc along the center of the rectangle.

I can't seem to apply a perpendicular relationship to a line crossing an arc. How is this accomplished?

When I select a line and an arc should a perpendicular relationship not be available? I only get a tangent.
• ###### Line perpendicular to arc
I don't think this is directly possible.

A two-step process however:
Create a construction line that is tangent, then make your line perpendicular to that line.

or

Create another line that goes through the centerpoint. A line that goes through the centerpoint will always be perpendicular wherever it crosses the circle.
• ###### Line perpendicular to arc
Thanks, a construction line through the center point did the trick.

Odd, in SolidEdge you can apply a perpendicular relationship between a single line and a single arc, surprised it can't be as easily done in SW.

(actually not too surprised...)
• ###### Line perpendicular to arc
you can not add perpendicular relation but if you follow the steps you can draw a line which is perpendicular to the arc.
select the arc
start line
click not on the arc & drag the mouse
you will find yello line passing thru the center of the arc
now follow the yellow line & click on the intersection point of arc.
I hope its not very difficult.
• ###### Line perpendicular to arc
Thanks for the suggestion. That also works, but like you mention, does not add a perpendicular relation.

Any idea why SW won't allow a perpendicular relationship between an arc and a line? Definitely geometrically possible so why won't it offer this when a line and an arc are selected?
• ###### Line perpendicular to arc
I can't answer why. The perpendicular relation is available for splines, ellipses, and parabolas. For arcs, it would be redundant, but helpful to those legions who have forgotten junior high school math.

In ninth grade we learned that a line through the center of an arc is perpendicular to the arc where they cross. It is a truth in geometry that you can comfortably rely on without feeling like it is an approximation or compromise.
• ###### Line perpendicular to arc
Thanks for the accurate, albeit condescending response. I am aware of the geometric laws, just wondered why SW can simply apply a perpendicular relationship between a line and an arc with extending the line to the centre of the arc.
• ###### Line perpendicular to arc
maybe put in a request for it?
• ###### Line perpendicular to arc
Tim, you don't have to actually extend the endpoint of a construction line to the center of the arc. You just need to apply a coincident relation between the line and the arc center. It would be nice to be able to apply a perpendicular relation directly to the arc instead of having to deal with the center point, but using a coincident relation is still just a single step process. That's probably why SW hasn't bothered to change it.
• ###### Line perpendicular to arc
Mahir

Sometimes those centerpoints are hard to find. A perpendicular to an arc would be easier to set.

Dwight

• ###### Re: Line perpendicular to arc

10 years later and still no perpendicular relationship...  Not to worry, I'll keep drawing additional perpendicular construction lines and then adding a tangent relationships because that's far more efficient!

• ###### Re: Line perpendicular to arc

Hi Will,

Thank you for expressing your concerns regarding this enhancement request.

I am attempting to escalate the severity of this request with the sketching tools team as there has been a demand to implement this relation for some time. I realize many users would find it useful for the growing number of 3D sketching and surfacing features that have recently become available.

To help escalate this issue, I would suggest submitting a service request which describes why this issue is needed and to what extent this feature would increase your efficiency.

Thank you,

Kyle