TANGENT LINES

[oldman]

I have been trying to make tangent three lines originating from the same plane at different distances down the plane tangent to a circle. I can tangent two lines, but when I try to tangent the third line. It gives me interfering dimensions. Can you tangent three lines to a circle or not? I am trying to create a pivot point for the three lines.
Edited by: oldman

 

[CPiotrowski]

maybe post an example of your issue.

 

[mjcole_ptc]

When you draw your three lines make sure that you don't get any H or V
constraints or point on entity for the lines. Then add your tangent
constraints and then add your dimensions. I just did it and had no
problems.

 

[oldman]

Thank You. I'll give it a try today. I don't get any H or V constraints as my lines are all on angles.

 

[oldman]

I gave it a try yesterday. It works until the last dimension. I can give the three angle dimensions and two of the length dimensions. The problem comes on the last dimension. I am trying to keep the angle dimensions and three dimensions down a center line on a plane. The last dimension on the plane is when the interfering dimension note comes up.

 

[SW]

I think I've had the same problem on previous occasions. I'd be interested if anyone has an answer.

Sam

 

[mjcole_ptc]

With the tangency constraints between the lines and circle, you will
only be able to dimension the line with one linear dimension because
the circle tangency will determine the other orthoganal dimenion for
you.



Follwing is the situation if circle is snapped to the origin.

Circle 1Dim

line1 3Dims 1Placement 1Angle 1Length

line2 3Dims

line3 3Dims



A picture would be an ideal way to diagnose what problem you are running into.

Try to make it smaller so it can be good quality but not take up a lot of space.



Michael

 

[oldman]

Your sketch is close, only all three of the angled lines need to be tangent to the circle.A pivot point is the center of the circle. I wouldsketch a drawing, butI haven't figured outhow to attach it to this forum yet.

 

[mjcole_ptc]

I used Sony Image Station for my picture posting it's one of many free
sites that allow you to post pictures. Although I think Sony is a poor
company which makes products with short life spans I'm not paying them
anything so it's no loss to me.



I do not advocate using their site but it's worked for me so far and you can sign up using the following link.



https://secure2.imagestation.com/shop/sony/secure/join/joi n.html



Once you have an account you can create Albums and upload bitmaps or jpegs from your hard drive.



When you have your picture uploaded you can right click on the
image when it displays and select Properties and copy the full location
http://***/****/*******.jpg and use the add image icon on mcadcentral
and just paste the location in the window that pops up.



If the lines are coincdent with the circle the angle and one linear
dimension should be required to locate the line. It seems though that
when adding the tangency constraint Pro/E seems to take into account
the direction that the line is going as it extends away from the circle
into account. The best way to control this so you can get any tangency
angle in either direction seems to be with an angle of 0-360 and either
a positive length to keep the same tangency direction or a negative
length to reverse the tangency direction.



This is very weird indeed. I had noticed problems with angles for
center lines in the past not being useable to pattern a feature in the
old days of Make Datum so I'd usually try construction lines. My
mind is warped enough from this for one day. I'll investigate this
problem more later.



Using centerlines and points on the circle may let you define the
angles and locations better but it seems due to the fact pro/e
considers the directions the lines go off the circle as an infered
constraint, you'll never be able to truly dimension your sketch fully
as you'd like to.



Michael