{{LEFT}}

## Cartesian Model to Three Dimensional Model

In a 2-axis Cartesian model, we have X axis running left to right and  Y axis running down to up.

Points in this model are defined by two values: X and Y. In Visual Effects and Surveying, we add a third axis to define points in three values.

For this, we use a three dimensional Cartesian Model with X, Y and Z axes. It’s important to note that, in Previzion, X-axis run back to front and Z-axis runs left to right.

In surveying, the same model applies, but the axes have a different name:

• Northing: X-axis
• Easting: Z-axis
• Elevation: Y-axis {{RIGHT}}

## Northing, Easting, Elevation to XYZ

When converting from the survey coordinate system from Northing,Easting,Elevation denomination to X,Y,Z denomination, flip the second and third values.

Just remember that Y is always up.  And in Surveying terms Y is Elevation. This difference is important to keep in mind because, in the survey files, Elevation, the Y-axis, is the third item, while in Previzion coordinates, Elevation is the second item in the coordinates.

• Northing = X
• Easting = Z
• Elevation = Y 