While using Vertical Design, you may notice a few settings in the Properties of your Vertical Design. Two of the settings found in your Vertical Design Properties are Search Distance, and Hit Length.
Search Distance - is a radius that is projected from spot vertical rules such as elevation. With the settings above, an elevation rule will search for objects 6.56’ from its placement in a circle. If it encounters an object in that search area, it will elevate the object to your defined elevation.
Hit Length - is a linear distance that is projected in the direction of your linear vertical rule. An example rule that uses Hit Length would be Cross-slope. With the settings above, a Cross-slope rule will search forward from its end point 16.40’ and will stop at the first linear object it encounters, and then elevate that object. Hit Length will only compute forward from the Target Point and backwards from the Source point to find a “Hit”. It will not look Forward from the source point or backwards from the target point.
Below is a short video explaining these two options in Trimble Business Center.
Vertical Design - Search Distance and Hit Length