Field General® - GPS Machine Control Model Creation

Maximum productivity and more profit. Productivity increases using machine control systems lead to less labor, less fuel, less machine maintenance, and ultimately, more profit.

Field General allows contractors to create 3D machine control site models easily, allowing the maximum return on investment.

How does a machine control system work?  A machine control system compares the current location of a machine blade with the desired grade at that location and either displays the difference (indicate systems), or automatically makes a blade adjustment.

The current location of the machine is obtained either by GPS (Global Positioning System) or a robotic total Stations, after orientation to the site using known control points.

TriangulationTriangulation.  The desired grade at each location is provided by a special file containing a Triangulated surface (TIN).  Unlike a staking file, a triangulated surface file contains a 3D elevation for every location on the site.

To understand how a TIN file works, study the animated file to the right. The known spot elevations (30,29, 31) at the corners of the triangle are used to interpolate any elevation on the triangle.

Three calculated points are shown, but a machine control system using this triangle for desired grade could sample this triangle anywhere and get a grade. Triangulation files normally contains thousands of these triangles.

Making a Machine Control Model.  Traditional grading using grade stakes requires operators to possess an understanding of grading objectives between stakes.  This is done on the site using the information available on the site plan.

See it with 3D Live.  3D Live allows the GPS model to be visualized in 3D, while simultaneously being revised in 2D.

3D Live

Here's how it works:  Use the editing tools in plan view while simultaneously viewing the 3D model.  Changes to the plan view are immediately shown on the 3D.  Here is a low resolution example of a side by side 2D and 3D screen. 

Edit the line work and see the changes.

Building a Machine Control Model.  With machine control systems, proper interpretation of grade between known data points needs to be done to the file before it can be used.  Many buyers of machine control equipment are lead to believe a CAD file will create a machine control file.  A CAD file is the beginning of a good model, but it requires much more to become a model.

uncorrected road model

Consider the illustration above. It is an uncorrected file obtained by loading the CAD file, and triangulating the proposed information.  The highlighted blue triangle does not hold the crown of the road properly.  A study of the file indicates many other problems.

Here is the same file corrected, using offsets, trims and snaps, for machine control grading:

Corrected Road Model

The machine operator sees this on his display (courtesy Topcon Positioning Systems), and the blade is constantly adjusted to the desired value from the triangulated (TIN) surface model.

Topcon Machine Control Simulator

Creation of surface models for Caterpillar Accugrade, Leica PowerGrade 3D systems, Sokkia GPS, Topcon's 3DMC2, Trimble's Grade Control System and LandXML are fully supported by Field General.

Call us at 1(877)746-7483 to set up a demonstration of how InSite SiteWork and Field General can import and export points, offsets and create machine control models

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