3.3 Points, Lines, and Regions
Points and Lines
- Points and lines form the basis of the drawing geometry.
- Tap the Line Tool in the Drawing tab of the tool palette and press and move your finger inside the drawing bounds to create lines and form the regions of your desired geometry.
- Lines drawn with the line tool will snap according to the snap preferences. It is helpful to have snap-to-points enabled for connecting line end points, and snap-to-lines enabled when drawing a line that intersects an existing line.
- When a line is drawn that intersects an existing line, the target line is split and a new point created there.
- Points common to multiple lines are automatically merged.
- MobiSlope automatically detects the lines forming the top ground surface of the drawing and draws them in bold.
- The Point Editor Pane is displayed to the right of the drawing. It contains a list of all the points that make up the lines in the drawing geometry.
- Tap the Edit Points button in the Point Editor Pane to edit the point geometry.
- You will be presented with a point marker for each point in the drawing geometry.
- Tap a point marker to edit the point location with text input.
- Drag a point marker to graphically move the point. It will snap according to the snap preferences. Points that are common to multiple lines will move together.
- Tap the Draw Lines button in the Point Editor pane to draw line geometry using the Line Tool.
Using the Select/Pan Tool to modify lines
- Tap the Select/Pan Tool in the Drawing tab of the tool palette, and tap once on a line in the drawing geometry to select it. Red circles will be displayed at the line end points to indicate it is selected. Now press and hold over the selected line and a menu will be presented with the following options:
- Add Point: Add's a point to the line at the location where you pressed.
- Trim Line: Trims the segment of the selected line to the nearest line intersection from where you pressed. Creates a new point at the trimmed location.
- Delete: Delete's the line from the drawing.
- Show/Hide Slope Angle: Displays the slope angle of the line.
- Set Tension Crack Zone: Modifies a surface line to have a tension crack zone to the specified depth below it. See Tension Cracks.
- Assign/Remove Reinforcement: Modifies a non-surface line to behave as a selected reinforcement material in the analysis. See Reinforcements.
- Regions are automatically detected by MobiSlope as areas that are enclosed by lines.
- Tap the Select/Pan Tool in the Drawing tab of the tool palette, and tap inside of a region to select it. The region will turn red to indicate it is selected. Now press and hold inside the region to fill it with a material from the current drawing stage or from the material library.
- Re-selecting, pressing and holding your finger over the region allows you to change or remove the material.
- There can not be "empty" regions prior to running an analysis. (ie. all regions must be filled with a material)
- If a line is drawn through an existing region with the Line Tool , the region is emptied and you will have to reset the region materials.
Other Considerations for Slope Geometry
- It is recommended to draw slope geometry that extends well past the crest and toe of the slope, to ensure that slip surfaces starting or kicking up farther away from the slope crest or toe, are analyzed.
- It is recommended to extend the drawing bottom well past the depth of the slip surfaces of interest. Slip surfaces that intersect the drawing bottom boundary will follow the bottom boundary and may result in unintended factors of safety being calculated.
- Lines that do not connect to another line with both ends (ie. dangling) are not allowed in the drawing prior to running an analysis. Similarly, lines that do not connect to any other lines (ie. stray) are not allowed in the drawing prior to running an analysis.
- It is recommended to have a geometry point at every intersection between lines. (ie. do not leave lines "crossing" with no common intersection point)
- The top surface of the slope geometry can not contain any "overhanging" lines, as depicted below (vertical slopes are acceptable):