Solidify Faces(面をソリッド化)

参照

Mode(モード):

Edit Mode(編集モード)

Menu(メニュー):

Face(面) ‣ Solidify Faces(面をソリッド化)

Extrudes the selected faces, turning them from an infinitely thin surface into a manifold mesh with volume.

The thickness can be changed in the Adjust Last Operation(最後の操作を調整) panel:

Thickness(幅)

Amount to offset the newly created surface. Positive values move inward relative to the face normals. Negative values move outward.

Mesh before solidifying.

Thickness(幅)が正のときのソリッド化。

Thickness(幅)が負のときのソリッド化。

参考

The Solidify(ソリッド化)モディファイアー does this non-destructively and has many more options.