Site Engineer in need of CAD help, co-ordinates / grids

[benny mac]

Hi guys,

 

Right, basically my problem is this. Im new to CAD by the way...

 

Ok so to start with to help you understand things that bit better. Im a site engineer. Normaly i dont need to use CAD as the architect would be on top of things enough that i could just take the drawings in paper form and just get on with setting the job out. Iv just started a new job and it seems that the achitect is a little lazy, so i have taken it apon myself to get my head around CAD.

 

My only real problem is this. The co-ordinate system. Dont panic though, i do understand co-ordinates quite well, to a point. By that i mean that i use them in my setting out process using my EDM (topcon)

 

Normaly i would have a building set out on what i know as a LOCAL grid. It means that say the best part of the building will be square to the grid. So say a brick walls northing will be the same all along a 10m stretch but obviously the easting will have changed by 10m.

 

The problem i have is that on the CAD file that the architect has sent me the drawing is on what i know as a global grid, so it has no real relavence to the building. Which makes things very tricky on site where i cant take a laptop.

 

NEARLY THERE.

 

OK, so what i want to do is this.

 

I was to open my dwg file using CAD.

I then want to take the whole building, and move it so that it is working on a easy to use grid system.

So by this i mean have the corner of the site to be set to say

 

200.000 E

200.000 N

 

Then have the building run square with the new grid.

I have randomly placed station points on my current drawing that i will need to keep relevant to the new easy to use LOCAL grid. Shouldnt confuse things as these stations are part of the drawing so should just convert to the new grid... right?

 

OK, so thats about it. Sorry if its not that easy to understand what im trying to achieve... Please feel free to ask away on any questions that might help me with sorting this one out!

 

Thanks so much in advance, really need to get my head around this before monday morning!

[lpseifert]

You may want to look into the UCS command (User Coordinate System). It allows you to have coordinate systems with varied origins and rotations. See here for a tutorial.

[eldon]

Open the Architect's drawing, then Save As using another name. That way you always have the original drawing to refer back to.

 

Then move the building and rotate it so that a corner is on a nice coordinate.

 

Most Architect's drawing that I have seen use mm as the drawing unit. If you can cope with this then good, otherwise you will have to scale the drawing so that the drawing units are metres. Watch out for the dimensions as these have to be dealt with separately. Then just pick off the coordinates in your chosen grid system.

 

I don't use the UCS method, because you can never see whether a line is along the grid. So much easier to rotate the whole thing, and crick your neck looking at the text!

[rik567]

hi

 

it may be easier for you too get the architect to set up your new grid if your building is complicated and has lots of drawings this limits your chance of having an error, also get used to the global system as this is easier for doing curved buildings as u can rotate the building for setting out any "squares" inside it.

[eldon]

With respect to Architects, you do NOT want them to change the drawing for setting out. They usually have never banged a peg in the ground, and normally leave the units setting to the default, i.e. four decimal places of millimetres, and angles to the nearest degree.

 

Do it yourself, and get it exactly for best use for you

[SW4MP DONK3Y]

Hi

 

I am not sure how you would do this using CAD but I am a site engineer and set local grids up for myself all the time. If you have msn let me know and I will guide you through it. It really is simple and can be done within minutes.

[Strix]

I had a similar problem in a new job, but adding buttons to my short toolbar for UCS object and UCS world enabled me to flick between the two according to which part of the drawing I was working on