Changes for v4.0 are:
— SMRoad tools can now use the face selection to smooth the road
— Adds a new SMRoad tool, SMRoad(Diff), which can separately smooth each side of a road
— Adds an ‘Auto load’ option in UIMan to choose if TerrainAxe is started when Max starts
— Adds a ‘Left drive’ option in RoadLineSys to create road marks for left-hand drive countries

TerrainAxe is available for Max 2012 to 2018 and costs $217. A demo version is available here.