Trying to cut out islands for curb grade , problem is top of curb is in the design, so when I try it wants to raise to top of curb.i should use one tip blade control ? Any help appreciated.
Try dialing in a vertical offset based on the height of the curb. That will let you grade the bottom of curb.
You can go into your menu, go under guidance method and turn "adjust to avoid overcut" to NO and it will allow you to cut into the design where the curb is. Just remember to turn it back to YES when you are done to prevent over cutting where you would not need to