建立曲面
曲面就像是一个有弹性的矩形橡胶片，NURBS 既可以表现如平面和圆柱这样的简单造型，也可以表现如雕刻曲面这样的复杂自由造型。
Rhino 中所有创建曲面的工具生成的物件都是相同的类型：NURBS 曲面，Rhino 带有很多直接生成曲面或通过现有曲线生成曲面的工具。
所有的 NURBS 曲面内部都具有一个矩形结构。
甚至于圆柱面这样的造型也可以看作是一个矩形面首尾相接构成的，相接的边缘处被称为接缝，即使一个造型看起来不是矩形结构，它也是通过矩形结构修剪或移动了边缘的控制点形成的。
封闭的和开放的曲面
曲面可以是开放或封闭的，两端开放的圆柱面，有一个方向是封闭的。
环状体在两个方向都是封闭的。
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).
从点建立曲面
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.
从曲线建立曲面
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.
从其他曲面建立曲面
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.
其他方法
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.