If you're in a construction mode (see Creating Shapes in the Shape Modeling Construction Modes [ Shape Animation ]) other than Shape Modeling or Secondary Shape Modeling, you will get this warning when you try to set shape keys.
If you just did some modeling that you wanted to store in a shape, which is the mostly likely situation, there are two ways in which you can fix this:
Click Cancel. In the explorer, select the deform operators which were meant to model the shape, then drag-and-drop them into the object's Shape Modeling region in its construction history.
Click Cancel. Delete or undo the deformations which were meant to model the shape, switch to a Shape Modeling mode, and reapply the deformations. (Switch to Secondary Shape Modeling mode for setting shape keys in relation to an envelope's animation).
If you want to store a shape that contains no deformation, click OK. The shape key is applied in the current mode:
If you're in Modeling mode, the deformation is applied to the object's base geometry. The deformation operator is put in the Modeling region of the object's construction history. The shape will not contain the deformation, but you can blend other shapes with this shape in the mixer, which is similar to blending with the object's reference geometry.
If you're in Animation mode, the deformation operator is put in the Animation region of the object's construction history. The shape will not contain any deformation.
