Fill
Reference
Mode
Sculpt Mode
Tool
Toolbar ‣ Fill
Works like the Flatten brush, but only brings vertices below the brush plane upwards.
Area Radius
Ratio between the brush radius and the radius that is going to be used to sample the area center.
Invert to Scrape
When enabled, holding Ctrl while sculpting changes the brush behavior to be the same as the Scrape brush. When disabled, holding Ctrl while sculpting, will push vertices below the cursor downward.