3.1   Drawing Bounds and Units

Drawing Bounds

  • The drawing bounds define the area where you can draw lines, piezometric surfaces and specified surfaces, ranges, point loads, and surcharges.
  • Note: Search grids can be drawn outside the drawing bounds.
  • To set the drawing bounds, select Define Drawing Bounds from the Drawing tab in the tool palette.
  • You will be presented with four blue markers representing the current drawing bounds.
  • Tap a marker to edit the drawing boundary with text input.
  • Drag a marker to graphically move the drawing boundary. If snap-to-grid is enabled, it will snap to the currently displayed grid lines.

Drawing Units

  • MobiSlope allows the units of length, force, and stress for a drawing to be specified in either Metric (SI) or Imperial (British).
  • Note: All material properties and surcharge loads must be specified with units consistent with the selected units for the drawing.
  • Note: Changing the drawing units does not automatically convert any of the length, force, or stress values currently specified in the drawing. For this reason, it is a good idea to define the drawing bounds and units before drawing the slope geometry and creating materials, although they can be changed later if necessary.
  • To set the drawing units, select Units button from the right toolbar.
  • The standard units of length, force, and stress used in MobiSlope are the following:

Length: (m)
Force: (kN)
Stress: (kPa)
Unit Weight: (kN/m3)

Length: (ft)
Force: (lbf)
Stress: (psf)
Unit Weight: (lbf/ft3)

Unit Weight of Water

  • To set the unit weight of water, select Units from the right toolbar buttons.
  • When changing units from Metric to Imperial or vice-versa, you will need to update the unit weight of water accordingly, generally to the default values listed below.
  • MobiSlope uses the unit weight of water to calculate pore pressures from piezometric surfaces, and to calculate forces generated from water-filled tension cracks. You should only change the unit weight of water from the default values if you are modeling fluids other than water.
  • The default values for the unit weight of water are:

Unit Weight of Water: 9.81 kN/m3

Unit Weight of Water: 62.4 lbf/ft3