Spot coordinates

[charliep]

I'm working on an unusually shaped building using RAC 2009. The setting out engineer is asking for coordinates.I have a survey drawing of the site in Autocad, and would like some advice on acquiring the coordinates of the building.

The way I understand it I will need to rotate the building to true north; import the survey drawing; locate a bench mark on the survey drawing and position the building relative to it.

Any pointers, corrections will be most welcome.

[iankids]

Although there is no reason why you couldn't do it in the main model, I generally create an rft specifically for the topo surface, and I would often use this if I need to model the surrounding buildings which are not part of the subject site.

My normal process is:

1. Clean up the surveyors cad drawing saving it as a new file and getting rid of any extraneous text etc which I don't need. Purge, clean up and purge again.

2. If the levels have been produced with a z co-ordinate you could try the "use Imported" in the toposuface and theoretically it would create the surface as documented. For myself, I have never found this to work well as often there would be odd drafting errors in the cad file which throws it out. Generally, I would simply import the cad file, use it as an underlay a copy the points and levels individually using the levels as nominated by the surveyor.

3. Link the topo file to the model file.

4. Move the toposurface down to a known level in the model

5. Once the toposurface is physically in the correct level on the model, the acquire the levels from the toposurface.

6. if you then create a new spot dimension or level( I call mine Shared) you can have spot dimensions and or levels either as shared levels showing the level as per the surveyors drawings or as project levels.

Cheers,

Ian

[charliep]

Thanks Ian, I'm not so much looking at levels but geographical coordinates. This is to enable the engineer to set the position of the building on site with the crucial corners in a north / east position.

[iankids]

Oops my bad! Should read the question more carefully!?!!