Use the Optimization Options dialog to specify objectives for the Grading Optimization to work toward while maintaining the constraints of the grading objects. Leveraging these tools and the Convergence Plots dialog, you can evaluate the results of the optimization and make changes to the grading object properties or the grading objectives to achieve different results when optimizing.

Click Optimization Options on the Optimization Toolbar to open the dialog.

GLOBAL CONSTRAINTS

These are globally applied constraints unless overwritten when a triangle lies within a grading object zone with different Min Drain Slope and Max Slope settings.

Min Drain Slope

Specifies the minimum required drainage slope as a percentage for any surface triangle. The direction of the drainage is determined by Drain Lines and Low Points.

Max Slope

Specifies the maximum allowed slope value as a percentage for any surface triangle. 33% is the default value based on the typical maximum allowed 3:1 slope in a grassed area.

Cut and Fill Constraint

Specifies optimization to Cut Only, Fill Only, or None (which allows Balance Cut-Fill objectives).

OPTIMIZATION

Iteration

Specifies the number of iterations that the optimization will attempt before it stops. If a solution is found within the tolerance parameter, it will stop before it reaches the maximum iterations. The Feasibility chart in the Convergence Plots dialog graphs the progress and errors at each iteration. You can stop the optimization before the maximum number of iterations is achieved.

OBJECTIVE WEIGHTS

The following parameters represent the three core grading objectives that are targets for optimization. The weights are applied as a percentage to reach the targeted objective. Zero means the objective is not considered, all other values are weighed against the values of the other constraints to proportionally consider more than one objective.

Balance Cut and Fill

Specifies the weight (0-100) with which to minimize the difference between total cut and total fill.

In the Cut-Fill field, you can specify target net volumes as defined by the Cut and Fill Constraint.

None: Specifies the target net earthwork volume from zero to a specific volume amount. Cut: Specifies the target net cut volume. This must be a negative number. Fill: Specifies the target net fill volume. This must be a positive number.

Minimize Earthwork

Specifies the weight (0-100) with which to minimize the total amount of earthwork (the sum of total cut and total fill). This tries to not raise or lower elevations unless constraints or other objectives require it.

Smooth Surface

Specifies the weight (0-100) with which to minimize the grade change between adjacent triangles on the surface. This effect smooths a surface.

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