It's based on the material you select for the surfaces of the element. You can control the hatch assigned to each material in the Attribute > Material menu.
By "stippled", do you mean "dashed"??? If so: there doesn't seem to be a line type parameter within the Parameters panel, so go to the Floor Plan and Section panel, make sure "Enable Object's Linetypes" is not checked, and set the "Symbol Lines" to the desired line type.
MacBook Pro Apple M2 Max, 96 GB of RAM AC27 US (5003) on Mac OS Ventura 13.6.2 Started on AC4.0 in 91/92/93; full-time user since AC8.1 in 2004