Create Block Dialog OptionsKeyCreator \ Create \ Primitive-Solid \ Block \ Create-Block-Dialog-Options
The following settings are contained in the Create Block dialog.
Choose the method by which the block is to be created.
Note that one or more of the parameters will be grayed out, depending upon what you have selected under Create By.
The options in the Axis section determine how the axis for the height dimension of the block is defined.
Choose the method of anchor position on primitive block to suite the situation for placement. If the anchor point is not where you need it, change on the fly using the alternate toggle as set in Tools>Options>Positioning/Selection>Generic Toggle.