Wednesday, December 18, 2013

Basic Survey and Model Coordination

This post is focused on the notion of a simple project, a single building or house and garage perhaps.

Conceptually Revit expects us to begin by creating a model using Project North, make it easy to put on paper first. That's because we often don't have a reliable survey at first. Once we get a survey we can import it and use it to acquire coordinates which will also define True North. If that process is consistent with yours then it looks like this.

  • Create your initial design using Project North orientation (meaning we aren't positive about orientation yet)
  • Receive the Survey file
  • Open the Site Plan view
  • Change the Orientation parameter to True North
  • Import the survey file using Positioning: Auto - Center to Center
  • Rotate the survey so it is parallel to the boundary you choose (rotating the "world" under the building)
  • Move the survey so it places the building in the correct location (moving the "world" under the building)
  • Manage ribbon > Project Location panel > Coordinates > Acquire Coordinates - select the survey file

Site before acquire coordinates

Site after acquiring coordinates

As soon as you acquire coordinates you should find that Revit reorients the view so that True North is up. If you examine your other plan views you'll see they still show Project North (based on the Orientation parameter for each view).

You'll also probably find that the Survey Point icon disappears off screen as Revit moves it to mark the 0,0 coordinates it acquired from the source file. If you examine the images closely you'll see the paper clip icon that is the Survey Point marker is not clipped. When you click on the icon it either un-clips or clips the icon. It doesn't move to mark the origin when it is unclipped. It just shows the coordinates for the icon relative to the origin instead. Unclip the icon before using Acquire Coordinates if you'd rather use the Survey Point icon to mark something within the site boundary instead.

Other Considerations:
  • What ground floor elevation do you usually show in elevations or sections? (0'-0", 100'-0" or actual elevation)
  • Will you create a toposurface from contours in the survey or placing points yourself? (May need to move the source file up/down depending on previous question)
  • Are there several or many buildings involved? (I recommend a different process using a Master Site model)
  • No CAD survey, just an old hand drawn document? We can enter property data using a table.

There are means to deal with each of the answers to those questions. You can refer to this SUMMARY POST for other related things I've written.

Here's a video demonstration of the steps plus some property and setback lines.

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