Surface Models for Machine Control

> How much time should you take to verify that all the engineering slopes and such are correct?

As much as it takes.
If there is an error in the plans and you don't catch it, it becomes your error.

Also, the detail sheets hold over the plan sheets. Because you KNOW the 2 will never match exactly.

After a while you will get to know which engineers are "better" than others.

Also the contract should contain language that the hard copy plans hold over digital files, should there be a discrepancy.

I'm not familiar with machine control files. But it is very convenient to highlight each grade and dimension on the plans after comparing it to a surface model.

Digital files are nothing more than a starting point for a model. I run dual monitors and import the cad file into the modelling software flavor of the day and run it on one screen and have cosstruction pdf's open on the other. As I work across a site I drag the pdf along with me and refer to the details sheets and grading plan view often to make sure everything is married up. As soon as i find differences the client or engineer is notified for resolution. One thing I do is contour my surface with a one tenth interval and no smoothing to scan for obvious areas of eratic grades.

The main issue I have ran into is making sure the contractor is on the appropriate control and calibrated to that control. Making sure they understand to check before starting and ending. Building the surface is the easy part.

Chevis, how about lunch one day? I am not far from ESP office.

Hey mate,
What brand of machine control file is it? You should be able to import the file into your survey/design package, which will have your DTM attached. Once in there I would create a road alignment and check the cross sections in your road design or analysis package.

For a starter, it really helps if you have a good 3D modeling software with good 3D viewer. Then you need to develop quality control procedures to make sure model is right.

As an example, some of the procedures may include:

Using quick profile routines with on real-time feedback on slopes
Creating models for each of the items
Running quantities, cross-referencing with contract quantities
Building cut / fill maps
Overlaying PDF on top of design in CAD environment
As mentioned, contouring at tight interval to find faulty areas
Using flyby over the 3Dmodels, which recreates the view of the operator in real-time
Etc.

How much time should you spend to make sure the model is right? As much as it takes. It has to be right. That's for sure.

Thank you guys for the input. All will be very helpful.

@DecSurvey - My Email is [email protected]. I could swing lunch one day. Let me know.