This is what I notice with the users I've run across through the years who rely solely on Ortho Mode. This is a simple example but it will serve as an explanation of the circumstances.
A line is drawn from 0,0 to 0,5. Then some more entities are placed in the drawing. The user needs to finish the feature to the end point of the line at 0,5. Yet his start point to get to the line is somewhere around 35,4.984375. The user then thinks he/she is connecting his line to the point at 0,5 but in fact his line is below it because of the Ortho Mode not allowing it to match to the end point of the original line. The people who use that method hardly ever go back and fix the corner connection because unless you really zoom in you can't see it but if you want to revise it and don't use Ortho Mode but running Osnaps and tracking, like I do, then I have two endpoint snaps at that place. That is usually how I find these errors. I can't get a precise endpoint snap indicator when there are two or more at an intersection of lines where they should all be lying on one point.
I hope that explains my point about using Ortho Mode. It is a nice feature but I wouldn't rely on it solely for accuracy unless I was drawing something which was measured in whole numbers and had only 90 degree angles.
Poster wrote....The user then thinks he/she is connecting his line to the point at 0,5 but in fact his line is below it because of the Ortho Mode not allowing it to match to the end point of the original line.
That isn't the fault of Ortho, that is an operator that doesn't know how to use the program properly. The "eyeballers" should be trained properly or shown the door.
People should be using Osnaps with Ortho or Polar on.
I have found similar problems with perpendicular snap, in my case using autocad 2004 version.
What I have observed, is that the point you use for the selection is used after, uselessly, for searching snap points from it, and apearing the perpendicular sign in an aparently arbitrary points.
In example if you want to move a line, after select the comand Move , when you need to select the object to move , you click in some arbitrari point of the line near the end (for example) and finishes the selection. This point, what is in the middle of the selection pointer, and not uppon the line itself ,is taken into account now when you need to select the starting point for the Move command, so if you wants to select the same endpoint of the line, the perpendicular snap sign apears to indicate that there is a perpendicular point in the line (very close to the end) than snaps perpendiculary with the point used for the selection, whitch is in the "air" necessarily because in the selection of the object the snap mode is not used by autocad.
I not understand what utility this feature can have, so I think this is a bad programation isue from autodesk.
From HELP: Perpendicular
Snaps to a point perpendicular to an arc, circle, ellipse, elliptical arc, line, multiline, polyline, ray, region, solid, spline, or xline.
Deferred Perpendicular snap mode is automatically turned on when the object you are drawing requires that you complete more than one perpendicular snap. You can use a line, arc, circle, polyline, ray, xline, multiline, or 3D solid edge as an object from which to draw a perpendicular line. You can use Deferred Perpendicular to draw perpendicular lines between such objects. When the aperture box passes over a Deferred Perpendicular snap point, an AutoSnap tooltip and marker are displayed.
I know that is not much help. The key phrase in that entire explanation is "draw a perpendicular line." There is no mention of the commands, MOVE, COPY, ARRAY, etc. This Osnap is not intended for use with those commands and has no effect. If you are trying to use the PERP Osnap with those commands, I suggest reading about the OFFSET command and how it may perform as desired.
There are two main ways to use PERP Osnap to draw a line: From and object and To an object. (You can also use it to go from and object, perpendcular, to another object, perpendicular, but these two explanations cover that scenerio when combined.)
FROM: Select the LINE command then immediately select the PERP Osnap button. Then click on an object. The start reference point will be flexible. Meaning that the start point of reference is undefined until an end point is selected. The line being drawn will remain perpendicular to that object, (not necessarily "on" the object, unless it is a closed shape). Once you have defined the end point, the line's start point will be defined and the line you are drawing will be perpendicular to that point of reference. (Not necessarily on the object unless it is a closed shape.) - I know this sounds redundant but when users say the line ends up in an arbitrary place, this explains why it may happen to appear that way. However , the start point of reference it is never arbitrary. Only perpendicular to the start point of reference.
TO: Select the LINE command, then select a start point of reference or object for the line. (The start point does NOT have to be an object.) The start point of reference will be static or locked, whether on an object or not. Meaning it will be the exact point where you clicked to initiate the LINE command. Then select the PERP Osnap button. Then select an object to define the end point of reference for your line. You do not have to select the exact location of the end point of your line, only the object or side of a closed object. (You may try, but you will not be able to do this anyway.) The PERP Osnap will automatically place the line perpendicular to that target object. The end point of your line may not be "on" your object, unless it is a closed shape. The line however, will be perpendicular to the second object of reference but not necessarily perpendicular to the object where you started the line.
You are not alone in experiencing this phenomenon. I too work on many of others' Cad files and just ran into this annoying issue again today. So out of curiosity I Googled to see what others' solutions may have been but found none and so here's my solution. At first I thought it would be as simple as using the flatten command to bring everything down to 0'-0" in the "Z" coordinate but after turning my plan view on it's side I could still see height to the objects, even though after an ID check of all line ends of the object stated they were at 0'-0" in the "Z" direction. So, what I did was selected the entire plan, back clicked my mouse, selected properties, clicked within the thickness tab and entered 0" (zero inches) and all is well. I know some time has passed since your request for help, and I hope you have resolved this issue since then but if not I hope this brings an end to your quest.
I completely understand your problem and have dealt with the dodgy yet at times very helpful perp osnap for many years. Unfortunately i am not here with a fix An explanation to the simpleton replying in this thread that do not understand the problem, perp is giving you a perndicular snap that is perpendicular to something else other than what you want and it overrides simple snaps like endpoint even when no original point has been given to be perpendicular too. It is like it is giving a perpendicular point to something nearby or a previous object, its most definitely a bug and i will endeavour to write a solution using visual lisp.
Funny, I've never had the problems with osnaps as you describe and I've been doing this since version 1.2. I think what you are seeing is ACAD trying to decipher which "set" osnap the user really wants. Try running PERP, NEA, and MID all at the same time to see what I mean. Many of the osnaps simply don't play well together so the user should really be choosing the appropriate osnap "on-the-fly" (Ctrl+right-click) . That method works much cleaner causing ACAD little confusion.
It's not the "command" causing the glitch, it's the user's application of the "command".
This was a known bug, identified as such by Autodesk. I forget which release, maybe 2012 or 2013, when it was fixed with a SP or at the next release. You can still see what is happening in 2014 because now you get two choices for a perp osnap under certain conditions. See attached and then you can replicate it for yourself.
Oddly, I've never experienced that so I'll acquiesce. Apparently it was a bug I was never aware of so there's really no need for me to now replicate it. That would just be a waste of my time.
Therefore, for, me, it's like it never existed.
I too have noticed an improvement for _Per in 2014, however this enhancement
has come with a bug that I have experienced more than three times since I
started using 2014.
The capture shows I wish to snap to the yellow vertical line using the grip-edit
stretch and a transparent override of _Per, however it will not do this for me,
not even with orthomode on.
I have not fully understood what is causing the enhancement to kick in
but preliminary thought is that it has something to do with the about-to-be
edited object will be shorter or longer than it's present state?
Running osnap for me is 559. Most everyone else here has thier's to 687.
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