Shared coordinates: publish, acquire, or specify?

[s.messing]

We are working on a super large campus plan (receiving information in dwg format from the “owner”). There are tons of buildings (over 25 separate structures) on a site that is slightly less than 2 miles in diameter around. It’s big. Did I mention that there’s a lot going on? The original campus that was given to us is in dwg format. The 0,0 of this CAD file is 36 miles from center of site! :!:


We created a Revit Site file (with topo using linked dwg underlays) with sea level as zero. We then created a main building file. We used shared coordinates to locate it within the site file (using sea level as it’s true zero and putting the actual building levels up at their true heights of 40 meters above sea level). We could then have each new building file be at its true height above sea level. When we link each new building into the main, centralized site file, they’d all already be at their true height(s) and ready to render (etc).


We now wonder if we should have left each new building’s project elevation at its original elevation of 0 meters (instead of adjusting it up 40 meters to start). We then could have specified coordinates to adjust from the perceived height to the true height in a secondary shared location so that the project coordinates would remain where they were and the shared coordinates would be the “adjusted” ones.


Questions:

1. Will the Revit model be adversely affected if the site and the project base point are within the “required” 2 miles radius, but the site survey point (shared coordinates/ dwg 0,0) location is outside of that two mile radius? – We think so, but hope not.

2. If this strategy doesn’t work (or maybe if it does) we could still choose to rebuild the whole situation from scratch (now before it gets any bigger) to work smoother from here on out. Unless someone knows of a way to avoid starting over completely…? Would it be more beneficial to leave the project elevation for each new building model at 0 (where it starts by default) and then specify the coordinates at 40 meters up in elevation? This would mean each new building model file would start in its default location in plan and elevation which we’d link into the site file and then publish coordinates to a secondary location in each file. Meaning that there would be 2 locations (one project internal and one shared coordinates) for each revit file.

3. Is there a better way to do this??!?:confused:


Check out the attached images for a visual of what we have done. Any input and advice is greatly appreciated, as always.

Cheers,
Stephen

[jeffh]

The distance between the survey point and the project origin should NOT affect the project performance. The survey point is just a way to coordinate your exported files with consultants. If you want the survey point closer you can "un-clip" the survey point and place it at a logical point closer to your project. You cna then clip the survey point back and specify coordinate at that point. This might make working with the file a bit easier by not having the survey point so far away. There is a pretty good article in the first issue of the AUGI AEC Edge magazine explaining some of the option related to shared coordinates. it is focused on Revit 2009 so the survey point is not mentioned but the concepts are still the same.

[Craig_L]

Would it be more beneficial to leave the project elevation for each new building model at 0 (where it starts by default) and then specify the coordinates at 40 meters up in elevation? This would mean each new building model file would start in its default location in plan and elevation which we’d link into the site file and then publish coordinates to a secondary location in each file. Meaning that there would be 2 locations (one project internal and one shared coordinates) for each revit file.
Cheers,
Stephen

With my limited experience at this I would say option 2 is the way to go.
I recently had a similar issue, but on a much smaller scale. We had adjusted the levels up to suit the actual levels rather than leaving the building at 0,0.
Needless to say we were in fact able to rescue this and move everything back down once we had realised the error of our ways, but it wasn't as simple as just moving everything down a few metres, at one point we had 1440 errors whilst trying to relocate the levels.
Leaving each individual model at 0.00 level and then sharing the co-ordinates is a much smoother operation and I would suggest that you go this direction.

Cheers

[Liz437]

If you want the survey point closer you can "un-clip" the survey point and place it at a logical point closer to your project. You cna then clip the survey point back and specify coordinate at that point. This might make working with the file a bit easier by not having the survey point so far away.

Wouldn't this result in the 0,0 acquired from CAD & thus the dwg itself being moved?