Model federation and geo-referencing

The current system of handling reference points (Global Origin/Survey Location, Project Location, Site Location) differs from the one used before BricsCAD V25.

Prior to BricsCAD V25, reference points could only be set by importing an IFC file and were stored in the BSYSLIB file (displayed in the Spatial Locations Manager dialog box under Site > IFC project points (relative to WCS)) and used for all DWG files of the BIM Project.

With the current system, you can also manually set reference points using the SETSURVEYLOCATION, SETPROJECTLOCATION, and SETSITELOCATION commands (add points from scratch or edit existing ones). The X, Y, Z coordinates and angle of the reference points are now stored in the DWG file. This allows you to set different points for separate files.

Adding reference points from scratch

The default value of the reference points' coordinates and angle in a new drawing is 0.

Set a Survey Location point in a drawing using the SETSURVEYLOCATION command. Toggle On/Off the visibility of the Survey Location marker by modifying the GEOMARKERVISIBILITY system variable's value.
Note:
  • The Survey Location point corresponds to the Geographic Location point. You can find its coordinates in the Position section of the Geographic Location dialog box (see the GEOGRAPHICLOCATION command article).
  • The angle value set for the Survey Location point corresponds to the NORTHDIRECTION system variable's value and represents the angle between the True North and the Y-axis, measured clockwise. Modifying the NORTHDIRECTION system variable's value changes the Survey Location angle value only if a GIS Coordinate System is set in the Geographic Location dialog box.

Set a Project Location point in a drawing using the SETPROJECTLOCATION command. Toggle On/Off the visibility of the Project Location marker by modifying the PROJECTLOCATIONVISIBILITY system variable's value.

Set a Site Location point in a drawing using the SETSITELOCATION command. Toggle On/Off the visibility of the Site Location marker by modifying the SITELOCATIONVISIBILITY system variable's value.

Note: Both the Project Location and the Site Location will show the True North angle of the drawing. Its value is taken from the True North angle set via the SETSURVEYLOCATION or GEOGRAPHICLOCATION commands.

Importing reference points

Reference points can be imported in an existing drawing by importing an IFC file where the points information is stored.

  1. Open the drawing.
  2. Run the IMPORT command and select the IFC file.
  3. In the IFC Import Settings dialog box set the model origin by choosing one of the available options:
    • Place IFC Global Coordinate system in WCS origin.
    • Place IFC Project Location in WCS origin.
    • Place IFC Site Location in WCS origin.
  4. Click Import.
  5. Save the drawing.

Existing reference points coordinates and rotation angles are overwritten by the information stored in the imported IFC file.

Exporting reference points

In case a Site, Project or Survey Location have been added in a drawing, these reference points will be used when exporting to IFC (via the EXPORT or IFCEXPORT commands).

When exporting from BricsCAD an IFC based project created with BricsCAD versions older than V25, which contains reference points stored in the old system, these will still be exported with the same results as before. In case reference points are added with the new commands, these will overwrite the old information during IFC export.

Note: Exporting to IFC, based on the old reference point information is not preferable, since not all information from the initial IFC import is stored in the project BSYSLIB file (for example, angle information for the Site Location). It is therefore advised to manually migrate the reference points.

Manually migrating reference points

There are two methods to manually migrate reference points information from BIM Projects based on IFC files saved with BricsCAD versions older than V25:

Re-import the original IFC file into a new drawing with the current BricsCAD version
  1. Open a new drawing in the current BricsCAD version.
  2. Run the IMPORT command and select the original IFC file.
  3. Save the drawing.
The Global origin/Survey Location, Project Location, Site location, and rotation angles are derived from the information stored in the imported IFC file and saved in the new DWG file.
Manually add the reference points with the current BricsCAD version
  1. Open the drawing in the current BricsCAD version.
  2. Add the Survey Location, Project Location and Site Location with the new SETSURVEYLOCATION, SETPROJECTLOCATION and SETSITELOCATION commands based on the information in the Spatial Locations Manager dialog box or in the original IFC file you imported into the drawing.
  3. Save the drawing.