How can I draw so that I don't get stairs when I do landscape material painting?

Hello. There may be a typo because I’m using a translator.
I want to express the golf course using the landscape paint function.I need to draw bunkers, fairways, tea boxes, greens, etc.
But when I paint, it’s not drawn in a curve like in the picture below, but it’s drawn like a staircase along the polygon of the landscape. I need to draw an accurate curve and circle.


If I use the Smooth function, the range or shape I want will be ruined. The landscape blend mode is currently set to -LB Height Blend.
Is there any way to draw a picture in the desired form on the landscape in this regard? Please let me know if you need to control the paint with blue print or set it up additionally. I need your help.