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CityCAD co-ordinate system

All elements within CityCAD are located using a 3D coordinate system.

The ground plane is always located in the x-y plane (i.e. when z equals zero). The x-axis is positive towards the east, the y-axis is positive towards the north, and the z-axis is positive in an upwards direction (i.e. towards the sky).

The coordinate units are determined by which drawing units are selected in the preferences dialog. If you change the units, this will not change the size of elements that are already drawn, but it will change the urban design grid and coordinate system.

Changing the position of the zero point

The zero point (0,0,0) is always located at the centre of the ground plane by default. You can change the location of the zero point by using the controls in the City Menu.
  • Go to City Menu: Set Zero Point: Set Ground Plane Centre in 3D View. Elements in your model will stay in the same position relative to the zero point, but the centre of the ground plane surface will move to the location you click.
  • Go to City Menu: Set Zero Point: New Zero Point Coordinates. You can then specify the x,y coordinates where you want the zero point to move to. Elements will stay in the same place relative to the zero point, but the ground plane surface will stay in its previous location.
  • Go to City Menu: Ground Plane Centre Coords. You can then specify the x,y coordinates for the ground plane centre. Elements will stay in the same position relative to the ground plane, but will be moved relative to the zero point.

Changing the orientation of the coordinate system

There are two ways of changing this.
  • Go to City Menu: City Orientation: Draw line towards new north. You can then draw a line in any direction on the ground plane and the coordinate system will be re-aligned in that direction. This is useful if, for example, you have imported a DXF base map with a grid, and you want to re-orient your CityCAD grid to align with it.
  • Go to City Menu: City Orientation: Rotate by a no of degrees. You can then type a number and the grid will be rotated around the zero point in an anti-clockwise direction by the number of degrees specified.

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