Manual/PartII/Meta Objects
Wikipedia，自由的百科全书
Meta Objects consist of spherical, tubular and cuboidal elements that can affect each other's shape. You can only create rounded and fluid 'mercurial', or 'clay-like', forms that exist procedurally, that is are computed dynamically. Use Meta Objects for special effects or as a basis for modelling.
变形球物体由能够互相影响形状的球形, 筒形和立方体元素构成。你只能创建圆形的和流体状的'水球', 或 '黏土状的'东东，让已经存在的物体'过程式'的变形，这些都是动态计算。变形球物体可以用来做特殊效果或基本建模。
Meta Objects are also called implicit surfaces, again to point out that they are not explicitly defined by vertices (as meshes are) or control points (as surfaces are).
变形球物体也叫做隐式面，在这再一次指明了他们不是用点（就像mesh那样）和控制点（就像曲面那样）显式的定义的。
Meta Objects are defined by a directing structure which can be seen as the source of a static field. The field can be either positive or negative and hence the field generated by neighbouring directing structures can attract or repel.
变形球物体是由静态域的源那样可见的定向结构定义的。这个域是正的或者是负的，这决定于生成域的相邻的定向结构之间是互相吸引还是排斥的。
The implicit surface is defined as the surface where the 3D field generated by all the directing structures assume a given value. For example a Meta Ball, whose directing structure is a point, generates an isotropic field around it and the surfaces at constant field value are spheres centered at the directing point. Two neighbouring Meta balls interact and, if they are close enough, the two implicit surfaces merge into a single surface (Two Metaballs).
隐式面是一个定向结构以一个假设给定值生成3D域的面。例如，变形球球，它的定向结构是一个点，在它的周围生成了一个各向同性域，这个有常数域值的面是以这个定向点为中心的。两个相邻的变形球球会互相吸引，如果靠得足够近，两个隐式面会合并成一个面（如图一）。 图一，两个变形球球
In fact, Meta Objects are nothing more than mathematical formulas that perform logical operations on one another (AND, OR), and that can be added and subtracted from each other. This method is also called CSG, Constructive Solid Geometry. Because of its mathematical nature, CSG uses little memory, but requires lots of CPU to compute. To optimize this the implicit surfaces are polygonized. The complete CSG area is divided into a 3D grid, and for each edge in the grid a calculation is made, and if (and more importantly where) the formula has a turning point, a 'vertex' for the polygonize is created.
事实上，变形球物体和能够进行逻辑运算和加减等数学运算的数学公式没有什么不同。这种方法叫做CSG,构建固件几何（Constructive Solid Geometry）。因为这是一个纯数学的方法，所以很节省内存，但是很浪费CPU资源。为了优化，隐式面都是多边形化的。完全的CSG区域分成3D栅格，为栅格的每一边都要计算一次。如果公式有一个转折点，栅格化在转折点上就会创建一个点。
To create a Meta Object press SPACE and select Add>>MBall. You can select the base shapes: Ball, Tube, Plane, Ellipsoid and Cube.
为了创建一个变形球球，你可以按空格键，然后选择添加-〉 Mball 。你也可以选择其它的变形球形：球，管，面，椭圆和立方体。
MetaBalls have a point directing structure, MetaTubes have a segment as a directing structure, MetaPlanes a plane, and MetaCubes a cube. The underlying structure becomes more evident as you lower the Wiresize and raise the Threshold values in the Meta Ball Panel.
变形球球的定向结构是一个点，原管定向结构是一个段，变形球面的是个面，原体的是个立方体。这些底层信息都可以在meta ball 面版中，通过降低线的分辨率和调高锐化程度来理解。
When in EditMode, you can move and scale the Meta Objects as you wish. This is the best way to construct static - as opposed to animated - forms. Meta Objects can also influence each other outside EditMode. When outside EditMode you have much more freedom; the balls can rotate or move and they get every transformation of the Parent Objects. This method requires more calculation time and is thus somewhat slow.
在编辑模式下，你可以随意移动和测量变形球物体。这是构造静态-相对于动态-的窗体的最好方法。变形球物体也可以在编辑模式外互相影响。在编辑模式外你有更多的自由：球可以旋转或移动而且它们可以获得父物体的任意转换。这种方式要求更多的计算时间因此也有些缓慢
The following rules describe the relation between Meta Objects:
- All Meta Objects with the same 'family' name (the name without the number) influence each other. For example "MBall", "MBall.001", "MBall.002", "MBall.135". Note here that we are not talking about the name of the MetaBall ObData block.
- The Object with the family name without a number determines the basis, the resolution, and the transformation of the polygonize. It also has the Material and texture area and will be referred to as base Meta Object.
- Only one Material can be used for a Meta Object set. In addition, Meta Objects save a separate texture area; this normalises the coordinates of the vertices. Normally the texture area is identical to the boundbox of all vertices. The user can force a texture area with the TKEY command (outside of EditMode).
- The fact that the base Object dictates the polygonalization implies that, if we have two Meta Objects and we move one of them, we will see the polygonalization of the non-base Object change during motion, regardless of which of the two object is actually moving.
接下来的规则将描述变形球物体之间的关系：
- 每一个有相同族名（名字去掉号码）的变形球物体能够互相影响。例如，"MBall", "MBall.001", "MBall.002", "MBall.135"。
- 不带号码只有族名的物体决定了栅格化的基础，分辨率，还有转化。和变形球物体相关的还有材质和纹理。
- 一个变形球物体集只能使用一种材质。另外，变形球物体保存了一个独立纹理区域；这使点的坐标一般化。一般说来，纹理区域和所有点的闭合壳子是等同的。用户可以用TKEY强制转换纹理区域。
- 基础物体决定多边形化的事实指出，如果我们有两个变形球物体，我们移动其中一个的时候，我们可以看到非基础物体多边形化的改变，不管这个基础物体是不是真的在移动。
The Meta Ball Panel in Editing context offers few settings.
If in Object Mode, only this Panel is present. You can define the polygonalization
average dimension both in the 3D Viewport via the Wiresize
Num Button, and at rendering time via the Rendersize
Num Button. The lower these are, the smoother the Meta Object is, and the slower
its computation.
变形球球菜单面板在编辑环境提供少数的设置。如果在对象模式，只有这个面板是显现的。你可以在3D视图通过线宽度（Wiresize Num）按钮，在透视图通过渲染度（Rendersize Num）按钮定义多边形的平均维数。度数越低，变形球物体越平滑，它的计算也越慢。
The Threshold Num Button is an important setting for MetaObjects. It controls the 'field level' at which the surface is computed. To have finer control, when in EditMode, the Stiffness Num Button of the Meta Ball Tools Panel allows you to enlarge or reduce the MetaObject's field of influence.
阀值按键对于变形球物体来说是一个很重要的设定。它决定了表面计算的域值水平。为了更好的控制，你可以在编辑模式下用变形球球工具菜单面板上的硬度键来增大或者减小变形球物体的作用域。
In this latter Panel you can also change the Meta Object type and set it negative (that is subtractive, rather than additive) with other Meta Objects of the same set.
在下面的面板，你可以改变变形球物体的类型，你可以把它和同一个集里的变形球物体设成负的（带负号的，和正号相对）。
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