From Inroads help Grid Volume(aka Borrow Pit method ) quickly estimates the cut and fill volume between two surfaces. Whereas the Triangle Volume command very precisely computes the volume between two surfaces, grid volume approximates that volume by overlaying the surface with a grid mesh, then tallying the cut-and-fill volume of each grid cell. You have control over the size of the grid cells, with smaller cells resulting in more accurate volume calculations — but taking longer to process. Workflow Create a grid over the area to be graded Smaller cells → More accurate For each grid cell Find the average change in elevation by determining the elevation difference for all four corners of the grid cell The volume is calculated by Adding the averaged cut & fill volumes separately Then multiplying by the area of one grid cell When To Use This Command You would generally not use this command unless your survey data was taken in a grid pattern in the field, for instance, in rows and columns 10 meters apart. However, even if the survey data is not in a grid pattern, you can use this command as a check against other volume computation methods. Also see measurements chapter from old Smart3DCapture help: https://communities.bentley.com/products/3d_imaging_and_point_cloud_software/f/contextcapture-descartes-pointools-forum/152879/contextcapture-measurements-chapter In Contextcapture Acute3D Viewer the grid is only shown visually without option to extract value for each sampling grid. I think this method is used in Contextcapture because it is faster to calculate and it minimizes wrong volumes because of surface noise.
↧