Trimble Business Center

I am looking for the best way and quickest way to create an intersection subgrade. Ideally this would be tied to the intersection created by the intersection tool, so if anything changes the subgrade would change as well.

I tried using the Create Subgrade command found within the Corridors tab but that creates vertical faces around the subgrade up to the finished design, this would create issues for a machine control model. I also tried adding lane edge delineation to my subgrade breaks in the corridor template but this did not work either. I think (could be wrong) the corridor templates will not support "stacked" intersections (finish grade and subgrade).

Thank you!

Currently you kind of have two choices

1) You can use Apply Site Improvements to areas of the Intersections and then Create Subgrade Surfaces from the Site Improvements Applied - these are applied Vertically inside the areas of the Intersection so don't tie out to Sideslopes etc. Note that to Render an Intersection, the Intersection tool applies Surface Textures to the areas of the Intersection, and you can just find those dots and change their properties to apply a Site Improvement Stack to the same areas - however these get replaced each time the Intersection gets updated so you don't want to do that till you are 100% happy with the Intersection Model. You may also want to adjust the way you model the Corridors that are used to create the Intersection around the Curbs, so that you have a Flat Bottom to the Curb in the Finished Grade Model underneath which you can apply Site Improvements - and then Model the Top of Curb as a separate Surface above the Finished Grade so that you can capture the quantity of Curb Concrete - that way you can model the Pavement Stack, the C&G Stack and if you need to a Sidewalk Stack to create the subgrade surfaces - I have managed to do that quite successfully in certain situations - note you need to tag the Bottom of Curb and Sidewalk elements as "Shoulder" in the Corridor Models and then they are modeled by the Intersection Command into the Intersection. 

2) If you have complex subgrades that project out to a sideslope detail then you will need to model those using either the Sideslope command and then add the strings to the subgrade models created above to extend the subgrade surfaces out to the daylight with the sideslope. I have also modeled subgrade surfaces using Sideslope command to create all the strings required and then selecting those strings to make the subgrade surfaces.

This is an area that we have to work on still to create continuous finished grade and sub grade Models through Intersection or Composite modeling areas - it is not a straight forward problem to address. Some people just copy finished grade strings down to sub grade layers and change their elevations by Material Thicknesses using Change Elevation command and then make surfaces out of the offset strings and that also appears to work well in many scenarios.

Alan