A 12 sided 3D shape is a dodecahedron.
A tridekahedron is a 3D 30 sided shape.
An 11-sided 3D shape is a hendecahedron.
A 12 sided 3D shape is called a dodecahedron.
A hexahedron is the name for a 6 sided 3D shape.
A five sided 3d shape is called a pentehedron
the name of a 20 sided 3d shape is called a icosahedron
A heptagon is not a 3D shape. It is a seven sided shape. It could be designed on 3D software if necessary.