I often get asked how to go about building a 3D model for an Excavator of a Utility Trench Network where two trenches come together at an intersection point. I recorded this video to show the processes that I would use to compute out the trench intersection and build a composite model for the machines.
You will be editing linework in 3D to get the intersection of the two trenches to come together - using commands like Linestring Editor, Trim/Extend, Break, Join, Quick Line and Insert Line Segment. The main challenges are handling the vertical walls and making sure that you don’t have crossing breaklines - especially if the two trenches have their inverts at different elevations.
Make sure that your final intersection model has slopes that meet your Health and Safety requirements and also make sure that the end model is simple and easy for the excavator operator to cut with the machine - a little bit of extra overcut is going to be saved in terms of the time trying to dig an over complex model.
The video shows you how