. Cylinder creates a solid or hole, created by extruding a circle vertically up or down. The appearance of a solid is determined by the current Perspectives Settings .
To add a cylinder:
1 On the Perspectives toolbarright click 3D Box 
. Click Cylinder.
The prompt reads "Center"
2 Click a center for your circular floor.
The prompt reads "point on circle or enter radius[previous]:"
3 Click a point on the circumfrence of your circle, type a radius and press ENTER, or right click to accept the default (previous radius).
The prompt reads "Height or depth[n]"
4 Either, for a solid: click a point above the base, or type a positive distance then press ENTER; or right click to accept the default default (previous) positive value.
Or, for a hole: click a point below the base, or type a negative distance then press ENTER; or right click to accept the default default (previous) negative value.