# Solid objects

A solid is a surface or polysurface that encloses a volume. Solids are created anytime a surface or polysurface is completely closed. Rhino creates single-surface solids, polysurface solids, and extrusion solids.

## Draw single surface solids

A single surface can wrap around and join itself. Example commands include Sphere, Torus, and Ellipsoid. Control points can be displayed on single-surface solids and moved to change the surface.

##### Ellipsoid

Draw a solid ellipsoid.

##### Sphere

Draw a solid sphere.

##### Torus

Draw a torus (donut shape).

## Draw polysurface solids

Some Rhino commands create polysurface solids. A polysurface consists of two or more surfaces that are joined together. A polysurface that encloses a volume of space defines a solid. Pyramid, Cone, and TCone are examples of commands that create polysurface solids.

The SolidPtOn command turns on grip points for polysurfaces, which act like control points.

##### Box

Draw a solid box.

Draw a cone.

Draw a cylinder.

##### Paraboloid

Draw a parabolic surface or capped solid.

Draw a pyramid.

##### TruncatedPyramid

Draw a pyramid whose apex is truncated by a plane.

##### Tube

Draw a closed cylinder with a concentric cylindrical hole.

## Create solid object from curves or surfaces

##### Boss

Extrude closed planar curves normal to the curve plane toward a boundary surface where the boundary surface is trimmed and joined to the extruded objects.

##### ExtrudeCrv

Drive closed planar curves in a straight line.

##### ExtrudeSrf

Drive surface edges in a straight line to create a solid.

##### Pipe

Create a surface, polysurface, or extrusion object with a circular profile around a curve.

##### Rib

Extrude a curve in two directions to a boundary surface.

##### Slab

Offset a polyline, and extrude and cap the result to create a solid.