Extrude

Hover inside a face with no segment in progress. A light overlay marks the extrusion target. Start the extrusion, move the mouse, then confirm. The face moves along its normal.

Key or gesture Action
Click a highlighted face Start an extrusion preview
Move the mouse Adjust the extrusion distance
Type a distance Set an exact distance in Blender units
Minus Change the direction of the typed distance
Backspace Correct typed distance; without input, cancel the preview
Click / Enter during the preview Confirm the extrusion
Esc / right click / Ctrl + Z during the preview Cancel it and restore the original mesh
Ctrl + Z after confirmation Undo the whole extrusion in one step

Undo affects the latest validated edit. Cancelling a preview leaves earlier edits in the local history; press Ctrl + Z again to undo the previous edit. An empty history does nothing. After leaving BagaCAD, Blender handles undo.

Extrude the new face into a volume.
Extrude the new face into a volume.

Several faces

Key or gesture Action
Shift + click Add / remove a face from the selection
Plain click on a selected face Extrude the selection
Enter with a selection Extrude along the last selected face's normal
Alt + click Replace the selection with connected coplanar faces and extrude them
Esc / right click before extrusion Clear the selection

For non-coplanar selected faces, the group moves in one common direction: the normal of the last selected face. Coplanar selection spreads only through shared edges, not corner contacts or detached faces.

Snapping

Height snapping is off by default and is active only while Ctrl is held.

Key or gesture Action
Hold Ctrl and aim at a vertex, midpoint, edge or face Place the extruded face plane through that snap point
Hold Ctrl during extrusion Enable height snapping; release for free movement
Orbit / pan / zoom Change the view while keeping the preview active

The face still moves only along its extrusion direction. A typed distance takes priority over snapping.

Result

Push a face inward to remove material from the same mesh.
Push a face inward to remove material from the same mesh.

Outward extrusion can fuse with volumes in the same mesh. Inward extrusion can make a pocket or a through-hole. The exact boolean calculation happens when you confirm and remains one undo step.

An isolated surface keeps a bottom and becomes a volume. Other objects remain separate.