How to rotate a drawing from a world grid to my local site grid?

Hi guys,

I'm a site based engineer and will very often recieve CAD drawing from the architect and structural engineer that are set to the world coordinated grid, so when i pick points from the drawing using the ID command i recieve a long and meaningless coordinate which is useless to me when setting out. does anybody know how i can rotate my drawing so that firstly its aligned with my grid and secondly give it the same coordinates as my site based local coordinated grid?

Many thanks

Richard:)

What I'll usually do in that situation is xref the client's drawing into mine. The UCS doesn't change.

What I'll usually do in that situation is xref the client's drawing into mine. The UCS doesn't change.

sorry to be a pain but how do you do this? im a beginer and have literally only just started using CAD:)

use command XATTACH and select their drawing. then you can move it or rotate it whichever way you like without changing the original. it's the AutoCAD equivalent of using tracing paper!

And you can also scale the x-ref, which is useful with architects' drawings which tend to be in millimetre units.

What's meaningless!!

i recieve a long and meaningless coordinate

Perhaps you should of listen on the training course you attended to become a "Site Engineer"

What's meaningless!!

 

 

 

Perhaps you should of listen on the training course you attended to become a "Site Engineer"

thanks kev thats really helpful:glare:

i havent been on a training course for CAD and have literally just started using it

i havent been on a training course for CAD and have literally just started using it

I can sympathize. Not one day of formal training, but I muddle through.

A handy command when xrefing is Align. If you have two or more points that correspond, you can pick one from the xref, one from your drawing, then a second from the xref, then a second from yours. If you feel it's necessary, you can give it one more set of points. Finally, press Y if you want AutoCAD to do the scaling too. It will line up the xref with your drawing, so you can get on with your life.

@ richiegriffo

i havent been on a training course for CAD and have literally just started using it

I never mentioned a CAD Course. I pointed out that you wrote, quote "so when i pick points from the drawing using the ID command i recieve a long and meaningless coordinate which is useless to me when setting out" unquote.

Why do you find the co-ordinates useless when you ID a point! A co-ordinate is a co-ordinate whether it is X Y or E N! How can the co-ordinate be useless, when you are setting out. What equipment are you using!!

Why do you find the co-ordinates useless when you ID a point! A co-ordinate is a co-ordinate whether it is X Y or E N! How can the co-ordinate be useless, when you are setting out. What equipment are you using!!

Perhaps you have not been on a construction site with the pressures. If coordinates have to be entered manually (which is the general case), every digit has potential for error. The more digits, the more potential for error.

When the drawing has Ordnance Survey coordinates with six significant figures for metre units, and then the architects are using millimetre units and have left the precision on default (four decimal places), there might be thirteen digits for the Easting and thirteen digits for the Northing. A great source for error. Simplification is needed. If the project is skewed to the grid, it is easier for the site engineer to have a row of columns all with the same Northing, for example.

I usually set a building up so the the extreme South Westerly corner has a coordinate of 0,0 and all main grids run orthogonally. Then coordinate numbers get much easier to handle, using the KISS concept.

Perhaps you have not been on a construction site with the pressures.

eldon

I know all about the pressures on site!

The OP stated that when he ID a point. Quote "so when i pick points from the drawing using the ID command i recieve a long and meaningless coordinate which is useless to me when setting out." Unquote.

Perhaps you could explain to me what the OP means as meaningless!

With reference to your Quote " When the drawing has Ordnance Survey coordinates with six significant figures for metre units, and then the architects are using millimetre units and have left the precision on default (four decimal places), there might be thirteen digits for the Easting and thirteen digits for the Northing." Unquote.

To me personally and others, when we get into situations where we are talking about thirteen digit figurers these can be shortened.

Example:

E 555555444.8883 N 444123555.9992

to E444.888 N555.999

Don't get me wrong, I agree with you that it is easier and quicker to use your own local grid system. But as I have stressed before with the OP "What is meaningless about the co-ordinates". So why bother sending the CAD drawing to the site engineer!

I personally would set my site up allowing for expansion as well eldon, perhaps the extreme South Westerly corner being E100.000 N100.000

I see we also have another question on the same subject: http://www.cadtutor.net/forum/showthread.php?71891-How-to-get-local-grid-on-CAD

Is this the same OP!