Perpendicular snap from line

I am wondering if it is possible to use the perpendicular snap somehow to
draw one line perpendicular to a base line from a specific point. I am
usually doing this when I lay out curves for a road. I know my pc or pt
point and want my line to be perpendicular from this point. Any help will
be appreciated.


--
Dennis Rich
D.T. Collins & Associates
1042 Mechem Drive
Ruidoso, NM 88345
(505) 258-5272

 

If you draw in this order the following will work. It does not use eh Perp
snap.

Draw the tangent coming into the curve. After drawing that line start the
arc command. When is asks for start point. You will now be drawing an arc
tangent to the line you just drew.

After drawing the arc start a Line command. At start point hit enter. You
will now be drawing a line tangent to the arc.

The commands must follow one after the other. If you do anything in between
you will not be able to pick up where you left off.

If the line work is already created and want to create a line tangent to the
PC or PT you can draw a line from the point to the center of the arc. Or you
can use Grips with copy & rotate to rotate a copy of the tangent @ 90D.

You could always buy LDD/Civil 3D. Commands to accomplish this and many
other facets of road design are included.

HTH
Allen

 

Or start a line away from your line and snap attach it perpendicular to your
line. Then move this new line to any point you wish.

 

Darryl,
Use polar snap and set it relative to the last segment. Then go to town.
I think that will do what you want.

 

<<Use polar snap and set it relative to the last segment. Then go to town. I think that will do what you want.>>

Doesn't that only work while you're drawing the lines? If the line already exists, it won't help, will it?

 

Yes. That's right. It sounded like he was in the process of drawing lines.
The end+per snap could be done programattically but I don't see that it
would save much time. One would still have to decide which way perpendicular
and also know the length.

won't help, will it?

 

Maybe I'm not understanding what you need, but you could offset your original line, then use Line, select a point on the original line then select the perpendicular point on the second line using the Perp osnap.

 

I can think of a couple simple ways.

You could do a polar array of the tangent line, centered at the PC/PT, with 2 objects filling +/- 90 degrees.

Or you could creat a new temporary ucs from the tangent line (Tools>New UCS>Object; it's faster than rotating the snap), draw your from the PC/PT with ortho on, and then switch back to the world (or previous) UCS.

 

Hi Darryl, Darryl and/or Darryl,

This will be the definitive answer. You can take my word for it! LOL!

You can choose the line command, then pick your point, then pick the perp o-snap (if it isn't already checked), then pick your "to" destination and that is where it will end. It will be perp to the line you choose from the point where you started.

And to everyone that said Darryl was referring to an endpoint, see original post below. No mention of endpoint anywhere.

*************

Posted by: Darryl Collins
Date: Feb/11/05 - 10:21 (CST)

Perpendicular snap from line

I am wondering if it is possible to use the perpendicular snap somehow to draw one line perpendicular to a base line from a specific point. I am usually doing this when I lay out curves for a road. I know my pc or pt point and want my line to be perpendicular from this point. Any help will be appreciated.
--
Dennis Rich
D.T. Collins & Associates
1042 Mechem Drive
Ruidoso, NM 88345
(505) 258-5272

 

It should be pretty easy to write a simple lisp routine that would do what
you are wanting to do...

Let me know if you would like that, and i can see if i can fit it in

Andy