How to Change Primitive Parameters in Blender

Changing the parameters of a newly added primitive shape in Blender is essential for setting the exact dimensions, vertex count, or alignment before you start modeling. This guide provides a straightforward walkthrough of how to access and use the "Adjust Last Operation" panel in Blender to customize mesh primitives immediately after creation, as well as how to retrieve the menu if it disappears.

Accessing the Operator Panel

When you add a new primitive object to your scene using the shortcut Shift + A (or through the Add > Mesh menu), Blender automatically generates a small collapsible menu in the bottom-left corner of the 3D Viewport. This is known as the Adjust Last Operation panel (or Operator Panel).

  1. Add your desired primitive object (e.g., Shift + A > Mesh > Cylinder).
  2. Look at the lower-left corner of the 3D Viewport for a panel labeled Add [Primitive Name] (for example, Add Cylinder).
  3. Click the small arrow next to the panel name to expand it if it is collapsed.
  4. Adjust the available properties (such as Vertices, Radius, Depth, Cap Fill Type, Location, or Rotation) by dragging the sliders or typing exact numerical values.

Using the F9 Shortcut

If you accidentally click inside the panel and it collapses, or if you prefer to edit parameters right at your mouse cursor:

  • Press F9 immediately after adding the object.
  • This opens the exact same "Adjust Last Operation" menu directly under your mouse pointer, allowing you to tweak settings without moving your cursor to the bottom-left corner.

Important Limitations

The parameter adjustment menu only works for the most recent action performed in Blender.

  • As soon as you click elsewhere in the 3D Viewport, select another object, move the newly created primitive, or switch to Edit Mode, the parameters for that initial creation are locked.
  • If you miss the opportunity to edit the parameters, you cannot reopen the menu for that specific object. You will need to delete the primitive (X or Delete) and add a new one (Shift + A) to modify its initial parameters again.