Precision input ? how to place a line xor y from an existing end point

This seems to be to simple to even ask but it's been a long time since
I used acad.
If I am placing a line from any given point and want to place the end
point at precise distance from an existing endpoint. How do I do this.
Lets say I snap to the endpoint and want to key in that distance..
either an x,y or distance and angle

Thanks for your help
Kirk

 

Hi

There is another way where you simply calculate the vector , ---- you can find
the points in the entity defination, then if what you ask is say 9/10 out the
line you devide the vector in 10 and add that to the point with Mapcar.
--------- Lisp is perfect for that kind of calculations , this one acturly let
you snap to a point you place between two points you point to in your drawing ;

(defun im (/ div dell a b)
(setq div(getint " How many points between endpoints ? ")
(setq dell(getint " on what number point do you want to Snap ?"))
(setq a (getpoint "Point One : "))
(setq b (getpoint "Point Two : "))
(mapcar '- a
(mapcar '* (mapcar '/ (mapcar '- a b) (cons div(list div div)))
(cons dell(list dell dell)))
))

The interesting part is the Mapcar calculations.

P.C.
http://www.designcommunity.com/scrapbook/2821.html

 

Lisp is good, but many don't know how to use it. There is a CAL
command, which enables you to enter mathematical expressions directly,
and you can use "osnap-terms" like variables. If you want a point at
1/3 of the distance between to other points, instead of writing
(2 * p1 + p2) / 3 you simply use osnap mode ENDpoint instead of the
points:

command: line
from point: 'cal
Tom Berger

 

hm, strange... why points this expression exactly to the middle between two
points? (adt 2004 sp1)

ain

 

Ain Vagula wrote:

Don't mind... I had osnap 'mid' on )

ain

 

Hi

Eh , ------- that case any resistant snap calculation will be overiden by the
build in Mid snap .
Please tell me if this discussion is a lead in the osnap discussion that been
going on for a long time, as if so , please realise that the standard snap
options is also the result of internal calculations with just one reson
, ----------- to yield a point .
Not to "snap" to the Mid, End or however you realise the build in Snaps, ------
but to calculate a point that automaticly replace the point you othervise would
point to.
In this concept a "Snap" could just aswell be the point 9/10 down a line instead
of the Endpoint snap , if this is acturly the Snap you need, and somtimes the
attitude of the standard Snap replace the knowleage about what Snap realy is ;
surely you most often need the midpoint or endpoint calculated within the Snap
function , but all sorts of "Snap" is acturly possible .
Anyway with the example I suggested , you can enter that Snap oppotunity
transperant by typing (im) , and if you are drawing a line, the Line function
will halt , and ask you about the two points that is then used in the
calculation, to find the Snap point 9/10 or whatever fraction down the vector
between the two points you then enter when the "(im)" function halt the Line
command ---------- or whatever other command that ask a point input.
Now if you are confused, please know that all I try to explain is, that if you
ask other types of Snap, then uncheck the standard Snap settings, and write a
few small calculations that you can trigger in the middle of a line or whatever
command that ask points, ------- did everyone forget the flexibility it give ,
when you can trigger your own Snap functions ?
P.C.
http://www.designcommunity.com/scrapbook/images/1775.jpg

 

Your question is not quite clear about whether the target end point of the
new line is located on the existing line or not. Anyway, why not simply
draw a circle at the existing end point with the radius equal to the
distance you want so that any point on the circle (locus) satisfies your
requirement. You can then draw the new line from the given point to the
desired end point on the circle, using snap, intersect, tangent, extend,
trim, etc.

 

But it does cut & paste.

Matthew

 

Unless I missed something...

use the <FROM> OSNAP

jimB

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Jim Bannister
3Dthinking dot com
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