WCS and UCS

[Mosese_Funaki]

Please help.

Is there a way to change or redefine the orientation of the WCS in AutoCAD (like UCS).

All my research and Uncle Google say it's impossible, but there may be someone here who can do it.

We have a site plan which shows a few tanks and structures drawn in the "real" WCS.

We also have this drawing with a defined UCS that lined up with my WCS. Is there a way to set the defined UCS as the new WCS in this drawing so I can xref this drawing without having to rotate it in the xref/drawing attached process.

Hope this make sense.

Thank you in advance.

[imadHabash]

Hi and Welcome to AutoCAD Forum,

as i understand ... in your site plan drawing type UCS >> World then PLAN command and double enter . Now you can rotate your drawing to the direction that you want . OR make your ucs direction rotated as you want then Ctrl+C all the elements and paste it Ctrl+V in your other drawing ( in this way you delete all unwanted ucs to match your other drawings ) now you can SAVE AS your dwg to a new site plan and start to delet all unwanted items and just keep your site in the new file and at proper coordinated place . OR you can keep every thing as is and just insert the angle value when you attache your site from xref dialog . 

Good Luck... 🙂

[Mosese_Funaki]

It really is impossible!

Thank you for confirming it Imad. Now I can stop looking for solution that doesn't exist 🙂

[leeminardi]

I am not aware of a command that will "change or redefine the orientation of the WCS in AutoCAD ".  However, with one command you can change the orientation of you entire drawing so that it correctly aligns with the WCS.

Assuming you know the location of the origin of the UCS in WCS coordinates, a point on the positive UCS  X axis and a point on the positive Y UCS axis you can use the ALIGN command as follows.

Command: ALIGN
Select objects: all
---- found
Select objects:
Specify first source point:                          <-- the ucs origin
Specify first destination point: 0,0,0
Specify second source point:                    <-- point on UCS x axis
Specify second destination point: 1,0,0
Specify third source point or <continue>:   <-- point on UCS Y axis
Specify third destination point: 0,1,0

[Mosese_Funaki]

Thank you Lee.

I am familiar with ALIGN command but can be a source of error. I thought if we can make the current UCS the new WCS it will eliminate possible errors.

Wishful thinking.....

[leeminardi]

Not sure what the source of error you have found with ALIGN.   I would assume it would use AutoCAD's full precision.  Try out this vlisp program and see if it is accurate.  It omits some of the potential for user error.   If the extents of the drawing are large, the target points (e.g., 1,0,0) cold be scale up  (e.g., 100000,0,0) to help precision.

(defun c:ucs2wcs (/ snp )
;; reoirents objects from current ucs to wcs.
;; L. Minardi 5/28/2018  
  (setq snp (getvar "osmode"))
  (setvar "osmode" 0)
  (setq	xu (getvar "UCSXDIR")
	yu (getvar "UCSYDIR")
	pu (getvar "UCSORG")
  )
  (setq	xw (mapcar '+ pu xu)
	yw (mapcar '+ pu yu)
  )
  (command "ucs" "")
  (command "align" "all" "" pu "0,0,0" xw "1.0,0,0" yw "0,1.0,0"  "")
  (setvar "osmode" snp)
)

[Anonymous · Accepted solution]

Yes you can.

Set the UCS to the orientation you need. WBlock the entire drawing and the new drawing WCS will be the reoriented UCS.