2 point spline curve

[deano33]

What changed between acad lt 2007 and acad lt 2012. Cannot draw a simple 2 point spline curve in 2012. Any ideas what has changed and how I do it? Is it a sys variable changed somewhere? please help.

[deano33]

What I am looking for is a 2 point spline and enter the start and end tangent like in acad lt 2007.

 

spline

pick first point

pick second point

enter

select tangent for start point end

select tangent for end point end

that is it.

 

how do i do this in lt 2012?

[ReMark]

When you have started the SPLINE command are you given an option to use Fit points or Control vertices?

[deano33]

Yes if I select method option = [fit/cv]

 

Have tried both options and do not get desired results.

 

fit results in a straight line and cannot get this to form a curve.

[ReMark]

I think you are not looking at your command line.

 

Command: spline

 

Current settings: Method=Fit Knots=Chord

Specify first point or [Method/Knots/Object]: M

 

Enter spline creation method [Fit/CV] : F

 

Current settings: Method=Fit Knots=Chord

Specify first point or [Method/Knots/Object]:

Enter next point or [start Tangency/toLerance]: T

 

Specify start tangent:

Enter next point or [start Tangency/toLerance]: T

 

Specify start tangent:

Enter next point or [start Tangency/toLerance]:

Enter next point or [end Tangency/toLerance/Undo]: T

 

Specify end tangent:

[deano33]

see attached picture of spline curve. I find it impossible to duplicate the correct spline curve created simply and correct in lt 2007 within lt 2012. It just not possible.

 

There must be a system variable set differently also as curv dis[playes differently in 2012 to 2007 even when exact same drawing is opened. In 2012 the curve moves a long way south out of display.

[ReMark]

Sorry I can't help further. That was my best shot. I think I've used splines maybe twice and that was three more times than I had anticipated doing so. You'll have to take it up with AutoDesk. I suggest making use of their Discussion Forums. Maybe someone there will have a better answer (possible solution?).

[rkent]

How about this method for drawing it, not sure why it displays differently from one release to another, that sounds dangerous.

Edited May 23, 2013 by rkent

[steven-g]

They did change it on you in 2011

http://heidihewett.blogs.com/my_weblog/2010/05/spline-tangent-direction-in-autocad-2011.html

alternatively when you have picked your starting point, and are asked to pick the start tangency, then you would need to pick a point in front of your spline on an imaginary line extending upwards from your starting point, which you can do using the extension osnap, I hope that makes sense basically in your sketch "ST" would be above "SP" and not below it.

[deano33]

Thanks guys. I have played with this and agree it does appear that you have to point in a different direction for point one. Prefered the old way though as it made more sense and easier to use. I have also tried this way and the spline curv dissappears off the top of the screen and curves back on itself. Opposite to example attached earlier but will not display as rkent detail above. There must be something wrong with my Acad install or a system variable set incorrectly somewhere that is forcing the curve to display incorrectly. It is as if there is a set distance offset. When I draw the spline it extends the first pick point line by a set distance in the direction of the first tangent point before curving back to second pick point. Any idease would be welcome. This is so anoying. Why did Autodesk try to fix something that was not broken?

[rkent]

Pick the first tangent point as the apparent intersection of the two lines rather than a random location.

 

You have to type T, enter, after the first picked point and T, enter, after the 3rd point. Just making sure since I can't watch over your shoulder.