Warp Flatten Tool

Drag with the Warp Flatten tool to level out the surface of a model in the direction of the view. Select this tool and the cursor becomes: .

Examples

Make sure your mesh has a high resolution - this is needed to get good detail out of the warp tools. This test model has had its resolution increased to 8000 in the object properties panel.
Here I have painted three steps on the model using the flatten tool.