Using Drain Lines and Low Points (Video)
Learn how to use drain lines and low points to affect the slope of your surface when considering drainage.
This video demonstrates:
- Drain Line grading objects
- Low Point grading objects
- Drainage grading objects influence on surface triangles
- Hydrology direction vector views
Transcript
Drainage slope in Grading Optimization is accomplished with drain lines and low points. Drain lines are created from lines in a drawing. The start of the line is the higher elevation, and the lower elevation is at the end of the line. Drain Lines cannot be a closed loop.
In the Optimization Options dialog, you can view and edit the Minimum Drainage Slope which must be greater than zero.
In the Wireframe view, you can see how the surface triangles are arranged. Each triangle that is to either side of the drain line will incline toward the line during optimization. Each triangle that is behind the drain line will incline toward the start of the line which is the highest elevation. Each triangle that is adjacent to or ahead of the drain line will incline toward the end of the line which is the lowest elevation.
The Hydrology visualization theme shows this slope inclination for each triangle.
Now we'll disable the Hydrology arrows and reduce the Balance Cut and Fill objective to zero to decrease the optimization time for this example. Viewing the slope elevations, you can now see how this drain line builds a channel for drainage.
Low points are similar to drain lines in how they influence surface triangle inclination during optimization. Each triangle attempts to slope down toward the low point. Low points are created from points that have been placed in a drawing.
By enabling the Wireframe theme and Hydrology, very similar patterns show the triangle inclinations toward the low point. In the Slope view, you can see how the depression is formed when the surface is optimized.
Understanding drain lines and low points in Grading Optimization will allow you to plan for efficient drainage in your project.