Where can I find this command?
The UnrollSrf command flattens (develops) a surface or polysurface with curvature in one direction to a planar surface.
指令行選項
Explode=Yes/No
是
The resulting surfaces are not joined.
No
The resulting surfaces are re-joined along the same edges that were joined in the original polysurface.
To specify where the unrolled polysurface will split
| 1. | Use the UnjoinEdge command |
| 2. | Select the edges that should be open after unrolling. |
Labels=Yes/No
Determines whether or not matching numbered dots are placed on the edges of the selected object and the resulting objects.
KeepProperties=Yes/No
Determines whether or not the selected object's properties are copied to the resulting object.
相對公差
Compares the maximum deviation of a curve from a line between its endpoints to the Relative Tolerance * length of the curve. If a curve is 10 units long and the relative tolerance is .01, the maximum deviation is compared to 0.1. If the line is 100 units long, max deviation is compared to 1.
Rhino 有一些指令可以建立或攤平可展開的曲面 (曲面上可以有洞或曲線)。
可展開的曲面就像是把無法延展、分離或收縮的材質捲起來一樣，例如：圓柱體、圓錐體及鋼板船殼。
展開後的曲面可以做為鋼板的切割路徑。
想像一下使用鋁箔建立您想要的曲面形狀，如果在塑形的時候鋁箔皺了或是破了，您想要的曲面形狀即是不可展開的。球體就是一個不可展開的例子，鋁箔無法伏貼地包覆在球體上，現代汽車的車體外型及擋風玻璃都是屬於這一類的造型。
Surfaces must still be linear in one direction for UnrollSrf to unroll them. You could lay a ruler along the surface and it would touch the surface from one edge to the other. These are called ruling lines.
尺規線
因為曲面有一個方向是直的，所以該曲面上的每一點的高斯曲率都是 0。Rhino 無法展開高斯曲率不是 0 或沒有任何一個方向是直的曲面。
因為可展開的曲面無法以任意兩條曲線建立，以 Loft 指令的可展開的型式建立的曲面型狀可能無法預期，形狀類似而且沒有銳角的曲線比較適合於建立可展開的曲面。
您可以使用高斯曲率分析找出曲面無法展開的部分。
可展開的曲面適用於設計機翼或水翼型式的曲面，但不適用於需要彎曲或展開金屬片的管路製作或布料剪裁。
When building a developable surface, you can get very different results depending on the complexity and similarity of the two edge curves. It is best if they are as simple as possible and have the same parameterization.
選取曲線時選取不同的端點可能產生不同的結果，有些時候您可以結合不同的結果產生較好的可展開的曲面。
可展開的曲面不必定是整平的曲面。
It is possible to make a developable surface that unrolls with a difference in area and ruling lengths from the 3-D surface. It is easy to miss the warning Rhino gives.
您可以展開無法展開的曲面。
Rhino does not have any method of making a surface a bit more or less developable. Some programs have a way of spreading out the concentrated fans of rulings that often occur, thereby smoothing the surface. Since metal, especially aluminum, has some elasticity, you can deviate quite a bit from a mathematically correct developable surface and still plate it up. Some builders that use developable surfaces in their models, expand the plates, and then add up to 1-inch chord depth of radius to the flat sides in the sections to make the plate "taut." The expanded plates fit up to the changed sections. They have not figured out how to get this "blow" into their 3-D models, though.
One way to approach the problem is to use the CurvatureAnalysis command to analyze the Gaussian curvature as a guide to surface creation instead of the developable loft. But there is no way in Rhino to expand surfaces created this way (unless they happen to meet the requirements for the UnrollSrf command).
許多設計師的設計需要重 3D 物件上的圖形展開為 2D 的平面圖形，3D 的曲面可以使用高斯曲率分析將曲面分為可以展開的與不可展開的兩種類型。
可以展開的曲面可以耗無誤差的展開成平面，例如：圓錐體、平頂錐體、圓柱體。
圓錐體、平頂錐體、圓柱體曲面展開後的情形。
球體或自由造型的曲面都是屬於無法精確展開的曲面。
Non-developable surfaces.
雙向都有曲率的曲面展開時會有誤差，僅適用於有延展/收縮性的材質。
The Curvature command will show the curvature curve as you move your cursor over the surface. The non-developable surface show the curvature with two arcs, to illustrate the compound curvature. Developable surfaces will show curvature with a single arc and a line, illustrating the curvature in a single direction.
可展開的圓柱曲面的曲率圓。
不可展開的球體曲面的曲率圓。
將不可展開的曲面展開成平面是一種複雜的運算，物件材質的延展性是重要因素之一。
It is helpful to imagine cutting and folding paper. A developable surface can be folded or rolled from a sheet of paper. Clearly, a sphere does not fit that criterion. A sphere of sorts can be constructed from a series of developable panels and can be developed panel by panel, but of course it will not be a true sphere, but an approximation. In short, if a surface can be constructed with paper, then it is determined to be developable and Rhino should be able to unroll it. If you need a sheet of rubber to make the 3-D shape, then it is non-developable and the UnrollSrf command will not unroll it.
A "sphere" made from developable panels.
The Smash command makes an approximate 2-D development of surfaces that have compound curvature. This command can be used to deal with fabrics that have a certain amount of flexibility and stretch.
請參考
展平雙向都有曲率的曲面。
將展開時必定會有誤差 (兩個方向都有曲率) 的 3D 網格或 NURBS 曲面展開為平面。
