Question about terrain sloping/grading

Hello. I am fairly new to BeamNG content creation, and I'm trying to make a map with roads and maybe some highways. After an extensive (and exhaustive) search, the only thing I found about grading was using the terrain flattening tool and slowly moving it across the two different elevations. The problem with this is that it's a bit too tedious and does not always yield a consistent grade. Does anyone know if there is a way to define two points and have the terrain flatten between them (perhaps like in Trainz)?