Topic: (AutoCAD LT) Do I have to worry about 'Z' Axis?

[craigr]

Since I am always drawing in 2d, (Strictly CAD LT), do I ever have to worry about the 'Z' Axis?

I simply assumed that if I never specify a 'Z' Axis, that CAD would automatically give it a value of '0'.

While browsing the Swamp topics, I ran across 'Z' not always being '0'.

I guess I could add the 'Flatten' command to my 'save' icon.

craigr

[tedg]

..I guess I could add the 'Flatten' command to my 'save' icon.

craigr

That's a good idea.
I believe Acad LT allows script files too right?
You could always run one that sets "Elevation" to 0 and runs the flatten command too.

Code: [Select]

flatten
all

elevation
0



[craigr]

So from your Answer,  my assumption that without specifying the 'Z' Axis, AutoCAD does NOT automatically set it to '0'.

Correct?

You would think that Autodesk would write that into the Code.

I guess I have several Workstations to modify the 'Save' Icon on.

Thanks

[tedg]

So from your Answer,  my assumption that without specifying the 'Z' Axis, AutoCAD does NOT automatically set it to '0'.

Correct?

You would think that Autodesk would write that into the Code.

I guess I have several Workstations to modify the 'Save' Icon on.

Thanks

I think it zero is the default, but if someone sets it to something else, that's where it stays unless someone changes it.
 
So if you receive a drawing that someone has changed it, and you do your work and don't know it, this would re-set it.
Even if you run the flatten command, the elevation doesn't get changed to zero.
 

[tedg]

I don't work in LT, so I'm not sure what you see when the elevation is set other than 0.
 
Do you get issues with lines not being co-planar?
 
Are you having issues with drawings having an elevation other than 0?
Or are you just being pro-active to prevent issues?

[JNieman]

Autocad does not randomly assign a Z value to any input as it sees fit.  It follows some pretty simple checks to see what the user specifies as display.  It can get fouled up easily when you're actively working in 3 dimensions and actively flipping things around or being all dynamic and stuff - especially if you're snapping to things with 3 dimensions and never looking at it from different angles.  It shouldn't ever be a problem for you, really.

If the sysvar "OSNAPZ" is set to "1" then it will always substitute the value of the sysvar "ELEVATION"(ELEV) as the z-value for that point in space.  So if you set:

OSNAPZ=1
ELEV=0.000

Then you should always have your stuff on the z=0 plane.  You will likely have to add those values to your startup lisp as I thnk OSNAPZ is only saved per-session.

Otherwise, having your own geometry at different elevations shouldn't really effect many things you do.  It mainly only rears it's head when you go to do "DIST" measurements and the output reads a very large number because there's a change in Z elevation that makes a line between to XY points longer than it appears in plane.  Otherwise, linear dimensions, text, all that fun stuff ends up being rather accurate.  So it's not a /huge/ deal if some of your objects are at a different elevation than others, but it can be a surprise when doing manual DISTANCE measurements at least.

[craigr]

Though I HAVE had a couple of issues throughout my 15 years of using LT, it is very rare. And, the only issue I had were with creating a Hatch. Even those issues were several years ago, so perhaps the newer revs of LT addressed that.

So, I guess I am being more Proactive, or maybe it is just being obsessed with everything being 'right'. - I HATE sloppyness!!!  - 

I HAVE been bit in the past within CAD by coworkers being 'sloppy' in their dwgs. To look at the dwgs, they look fine, but to go back and edit them, there are annoying issues. An example would be a straight line made of many segments. It looks fine and prints fine, but if you go to move it and click on ONE Segment, that one segment moves leaving the rest. - I had one CAD Guy that did this all of the time, even when I called him on it!! Thank goodness he is gone, it was very annoying and unprofessional.

Though admittedly, elevation isn't a big issue right now, non the less - Thanks for your help on this.

craigr

[tedg]

Autocad does not randomly assign a Z value to any input as it sees fit.  It follows some pretty simple checks to see what the user specifies as display.  It can get fouled up easily when you're actively working in 3 dimensions and actively flipping things around or being all dynamic and stuff - especially if you're snapping to things with 3 dimensions and never looking at it from different angles.  It shouldn't ever be a problem for you, really.

If the sysvar "OSNAPZ" is set to "1" then it will always substitute the value of the sysvar "ELEVATION"(ELEV) as the z-value for that point in space.  So if you set:

OSNAPZ=1
ELEV=0.000

Then you should always have your stuff on the z=0 plane.  You will likely have to add those values to your startup lisp as I thnk OSNAPZ is only saved per-session.

Otherwise, having your own geometry at different elevations shouldn't really effect many things you do.  It mainly only rears it's head when you go to do "DIST" measurements and the output reads a very large number because there's a change in Z elevation that makes a line between to XY points longer than it appears in plane.  Otherwise, linear dimensions, text, all that fun stuff ends up being rather accurate.  So it's not a /huge/ deal if some of your objects are at a different elevation than others, but it can be a surprise when doing manual DISTANCE measurements at least.

All good information here, the problem with setting varibables with and Acaddoc.lsp (or any LISP) isn't allowed in LT unless the OP has some third party applicatoin running to allow it.

[craigr]

JNieman - Thanks for all of that Info!!!

Sadly, OSNAPZ is not a command that LT recognizes.

- Bit by that ole 'LT doesn't do that' Bug!

craigr

[tedg]

Though I HAVE had a couple of issues throughout my 15 years of using LT, it is very rare. And, the only issue I had were with creating a Hatch. Even those issues were several years ago, so perhaps the newer revs of LT addressed that.

So, I guess I am being more Proactive, or maybe it is just being obsessed with everything being 'right'. - I HATE sloppyness!!!  - 

I HAVE been bit in the past within CAD by coworkers being 'sloppy' in their dwgs. To look at the dwgs, they look fine, but to go back and edit them, there are annoying issues. An example would be a straight line made of many segments. It looks fine and prints fine, but if you go to move it and click on ONE Segment, that one segment moves leaving the rest. - I had one CAD Guy that did this all of the time, even when I called him on it!! Thank goodness he is gone, it was very annoying and unprofessional.

Though admittedly, elevation isn't a big issue right now, non the less - Thanks for your help on this.

craigr

I agree, I hate sloppy cad work too! I like nice neat cad work with everything set correctly, purged as necessary etc.
:beer:

[JNieman]

Damn, worth a shot.  I never know what is/isn't allowed in LT until you tell me "didn't work!" haha - so I just try to throw some solutions at the wall and see what sticks.

Beyond that, I honestly don't know a great way to automate a correction.

I haven't used "Flatten" in a long time, but before you go adding that to the 'save' method, you might want to test it thoroughly.  Make sure it doesn't put everything on one layer, and what not.  I might be confusing it with other commands - but one of them just throws everything on one layer, one color, one linetype etc... which would be a pain.. especially if it's incorporated into the "SAVE" command!

[tedg]

Damn, worth a shot.  I never know what is/isn't allowed in LT until you tell me "didn't work!" haha - so I just try to throw some solutions at the wall and see what sticks.

Beyond that, I honestly don't know a great way to automate a correction.

I haven't used "Flatten" in a long time, but before you go adding that to the 'save' method, you might want to test it thoroughly.  Make sure it doesn't put everything on one layer, and what not.  I might be confusing it with other commands - but one of them just throws everything on one layer, one color, one linetype etc... which would be a pain.. especially if it's incorporated into the "SAVE" command!

That's why I was suggesting a script (which LT does allow).
Maybe craigr could test some command strings (as you suggested), to see what works and simply put them in a script or macro.
 
I too, don't know exactly what is or isn't available in LT, other than LISP and 3D commands.
 
Hope this helps you on your way Mr. craigr.

[JNieman]

Wait, hold on.

Surely there is still an acaddoc.lsp or some sort of startup lisp, right?  You just can't load EXTRA lisp files using appload, or whatever?

I mean how does LT work if there's no acaddoc.lsp?

It doesn't take anything other than notepad.exe to modify them.  Or is LT really locked down harder than I assumed?

It would appear so!

rkmcswain posts, in CADTutor, this bit of a tip on this issue:

Drawing-saved sysvars can be set in the template drawing(s).
Registry saved or non-saved variables can be set with a script file.

So there's that, at least.  Pulling up registry settings from a script is beyond what I'm comfortable suggesting, however.