This app generates grade diagrams at points on Autodesk® Civil 3D® TIN surfaces, visualizing the possible directions where grades fall within a specified range. It aids civil designers during the initial alignment/route selection process for any linear structure (road, canal, pipeline, etc.), where design criteria impose restrictions on the minimum and maximum allowable grades. By chaining a series of diagrams together, a first draft alignment with the desired properties can be constructed.

Upon initial invocation, the app will ask the user to pick a TIN surface, specify minimum and maximum grades, and input a segment/leg distance. Once these parameters are defined, the app will compute and dynamically draw the grade diagram at any point on the surface.

Grade diagram computation:

• The input point is projected to the surface to obtain an elevation.
• A total of n points are sampled on the surface around the perimeter of the input point at a distance d, where n is the number of envelope points and d is the segment distance.
• Grades are computed from the center point to point i.
• A line is drawn from the center point to point i on the perimeter if the absolute value of the grade is less than the maximum grade.
• An envelope correction distance is computed for every point i and all points along the perimeter are projected to the surface and connected to form a 3D polyline (the diagram envelope).

Please refer to the complete app documentation and the attached images for more details.

Note: This app uses a custom installer (and not the standard App Store installer).