Create surfaces
A surface is like a rectangular stretchy rubber sheet. The NURBS form can represent simple shapes, such as planes and cylinders, as well as free-form, sculptured surfaces.
All surface creation commands in Rhino result in the same object: a NURBS surface. Rhino has many tools for constructing surfaces directly or from existing curves.
All NURBS surfaces have an inherently rectangular organization.
Even a closed surface such as a cylinder is like a rectangular piece of paper that has been rolled up so two opposite edges are touching. The place where the edges come together is called the seam. If a surface does not have a rectangular shape, either it has been trimmed or the control points on the edges have been moved.
Closed and open surfaces
A surface can be open or closed. An open cylinder is closed in one direction.
A torus (donut shape) is closed in two directions.
Create surface primitives
3DFace
Creates mesh or SubD faces that can be standalone or added to an existing mesh or SubD.
Plane
Draw a rectangular planar surface.
Box
Draw a solid box.
Sphere
Draw a solid sphere.
Ellipsoid
Draw a solid ellipsoid.
Cone
Creates a surface cone.
TruncatedCone
Draw a NURBS truncated cone.
Cylinder
Draw a polysurface cylinder.
Torus
Draw a NURBS torus (donut shape).
Create a surface from points
PlaneThroughPt
Fit a rectangular planar surface through points.
SrfControlPtGrid
Draw a surface from a grid of points that represent surface control points.
SrfPt
Draw a surface from three or four corner points.
SrfPtGrid
Draw a surface from a grid of points that lie on the surface.
Create a surface from curves
DevLoft
Creates a single developable surface between two rails.
ExtrudeCrv
Drive closed planar curves in a straight line.
EdgeSrf
Create a surface from two, three, or four curves.
Fin
Extrude a curve on a surface in the surface normal direction.
Loft
Fit a surface through profile curves that define the surface shape.
NetworkSrf
Fit a surface through a network of crossing curves.
Patch
Fit a surface through curves and point objects.
PlanarSrf
Create a planar surface from planar curves.
RailRevolve
Revolve a profile curve around an axis and along a rail curve.
Revolve
Create a surface or SubD by revolving a profile curve around an axis.
Ribbon
Offset a curve and create a ruled surface between the curves.
Sweep1
Fit a surface through profile curves and one edge curve.
Sweep2
Fit a surface through profile curves and two edge curves.
Create a surface from other surfaces
CutPlane
Create planar surfaces through objects at specified locations.
Drape
Create a surface through the intersections of objects and points projected toward the construction plane.
OffsetSrf
Copy a surface parallel to the original.
VariableOffsetSrf
Copies a surface in the normal direction with different distances at specified locations.
UnrollSrf
Flatten (develop) a surface or polysurface with curvature in one direction to a planar surface.
Other methods
Heightfield
Create a surface based on gray-scale color values in an image file.
MeshToNURB
Duplicate each mesh face with a NURBS surface.
Symmetry
Mirror a copy of a curve or surface with continuity.