When you use modern day scanning techniques to survey rock faces of a large excavation, it is inevitable that you will pick up areas of the rock face that have overhangs. There are two tools in TBC that allow you to model surfaces that are not traditional surfaces i.e. those that represent surfaces that are either in the vertical plane or surfaces that have a variety of orientations including both horizontal and vertical elements.
In the video below we explore the use of the Radial Surface modeling techniques that utilize an alignment to define the “path” of the rock face and a TIN modeling method that was initially designed to model the inside of tunnels that has been modified for use in modeling rock faces in cuttings etc.
The radial method involves projecting all of the measured point data onto a cylindrical surface, and then using the Station (distance along the cylinder), Offset (Radial placement of the point around the circumference of the cylinder) and Elevation (perpendicular offset of point above or below the surface of the cylinder) in place of the traditional XYZ location of a point to determine the triangulation for the surface model. The surface after modeling will be in the normal location of the point data, it is just a different method of computing the TIN model that lends itself to the modeling of complex surfaces.
Once created, the surface model can be added to a corridor model using a surface instruction for the purposes of computing volumes along the rock face in comparison to an existing terrain model or a Design Surface model.
Video shows you how