We'll start looking at how 3D scenes are represented in Blender.
::我们将开始研究Blender如何呈现3D场景.

As was explained in  the "3D Geometry" module , Blender represents locations in a scene by their coordinates. The coordinates of a location consist of three numbers that define its distance and direction from a fixed origin. More precisely:
::正如在"3D几何"模块中解释的那样,Blender通过坐标表示场景中的位置.位置的坐标由三个数字组成,这些数字定义了从固定起源的距离和方向.更准确地说:

  • The first (or x-) coordinate of the location is defined as its distance from the YZ plane (the one containing both the Y and Z axes). Locations on the +X side of this plane are assigned positive x-coordinates, and those on the -X side are given negative ones.
    ::位置的第一个 (或x-) 坐标定义为它与YZ平面 (包含Y和Z轴的) 的距离.该平面的+X侧的位置被赋予正的x坐标,而在-X侧的位置被赋予负的坐标.
  • Its second (or y-) coordinate is its distance from the XZ plane, with locations on the -Y side of this plane having negative y-coordinates.
    ::其第二个 (或y) 坐标是它与 XZ 平面的距离,该平面的 -Y 侧的位置具有负的 y 坐标.
  • Its third (or z-) coordinate is its distance from the XY plane, with locations on the -Z side of this plane having negative z-coordinates.
    ::其第三个 (或z-) 坐标是它与XY平面的距离,该平面的-Z侧的位置具有负的z-坐标.

Thus the origin (which lies at the junction of all three axes and all three planes) has the coordinates (0, 0, 0).
::因此,原点 (位于所有三轴和所有三平面的交点) 的坐标为 (0, 0, 0).

Note:
The images for this tutorial were produced using Blender v2.46.
::需要使用Blender v2.46来制作本教程的图像.

Global and local coordinates

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Blender refers to the coordinate system described above as the global coordinate system, though it's not truly global as each scene has its own global coordinate system. Each global coordinate system has a fixed origin and a fixed orientation, but we can view it from different angles by moving a virtual camera through the scene and/or rotating the camera.
::混合器将上面描述的坐标系统称为全球坐标系统,虽然它不是真正的全球,因为每个场景都有自己的全球坐标系统.每个全球坐标系统都有固定的起源和固定的方向,但我们可以通过将虚拟摄像机移动到场景中和/或旋转摄像机来从不同的角度查看它.

Global coordinates are adequate for scenes containing a single fixed object and scenes in which each object is merely a single point in the scene. When dealing with objects that move around (or multiple objects with sizes and shapes), it's helpful to define a  local coordinate system  for each object, i.e. a coordinate system that can move with, and follow the object. The origin of an object's local coordinate system is often called the  center of the object  although it needn't coincide with the geometrical center of the object.
::全球坐标适用于包含单个固定对象的场景和每个对象仅仅是场景中的单个点的场景.当处理移动的对象 (或具有大小和形状的多个对象) 时,对每个对象定义一个局部坐标系是有帮助的,即一个可以随着对象移动和跟随对象的坐标系.一个对象的局部坐标系的起源通常被称为对象的中心,尽管它不一定与对象的几何中心相吻合.

3D objects in Blender are largely described using vertices (points in the object, singular form:  vertex ). The global coordinates of a vertex depend on:
::在Blender中,3D对象主要是使用顶点来描述的.顶点的全球坐标取决于:

  • the (x, y, z) coordinates of the vertex in the object's  local  coordinate system
    ::在物体的局部坐标系中,顶点的 (x, y, z) 坐标
  • the location of the object's center
    ::对象中心的位置
  • any rotation (turning) of the local coordinates system relative to the global coordinate system, and
    ::任何与全球坐标系相对的局部坐标系的旋转,以及
  • any scaling (magnification or reduction) of the local coordinate system relative to the global coordinate system.
    ::任何与全球坐标系相对应的局部坐标系的缩放 (放大或缩小).

For example, the teacup in Figure 1 is described by a mesh model containing 171 vertices, each having a different set of local (x, y, z) coordinates relative to the cup's center. If you translate the cup (move it without rotating it), the only bits of the model that have to change are the global coordinates of the center. The local coordinates of all its vertices would remain the same.
::例如,图1中的茶杯是由一个包含171个顶点的网格模型描述的,每个顶点都与杯子的中心相对具有不同的局部 (x,y,z) 坐标.如果您转换杯子 (不旋转它),那么模型中唯一需要改变的位是中心的全局坐标.所有顶点的局部坐标都会保持不变.

Coordinates of child objects
::子对象的坐标

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Figure 1b:  A parent serves as the source of the global coordinates for its child object. The child is the cup; the parent's orientation is shown with the colored arrows.
Animation of the above

Any object can act as a parent for one or more other objects in the same scene, which are then referred to as its children. (An object cannot have more than one direct parent, but parent objects may themselves be the children of other objects.)
::任何对象都可以作为同一场景中一个或多个对象的父,然后被称为它的子. (一个对象不能有多于一个直接父,但父对象本身可能是其他对象的子.

If an object has a parent, its position, rotation, and scaling are measured in the parent's local coordinate system, almost as if it were a vertex of the parent. i.e. the position of the child's center is measured from the parent's center instead of the origin of the global coordinate system. So if you move a parent object, its children move too, even though the children's coordinates have not changed. The orientation and scaling of a child's local coordinate system are likewise measured relative to those of its parent. If you rotate the parent, the child will rotate (and perhaps revolve) around the same axis.
::如果一个物体有一个父,它的位置,旋转和缩放是在父的局部坐标系中测量,几乎就像它是父的顶点一样.即,子中心的位置是从父的中心测量而不是从全球坐标系的起源.所以如果你移动一个父物体,它的子也会移动,即使子的坐标没有改变.一个孩子的局部坐标系的方向和缩放同样是相对于它的父母的方向和缩放.如果你旋转父,孩子将绕着相同的轴旋转 (也可能旋转).

Parent-child relationships between objects make it simpler to perform (and animate) rotations, scaling and moving in arbitrary directions. In  Fig. 1b  the teacup is a child object of the coordinate cross on the right. That cross is itself the child of an invisible parent. (It is both a parent and child.) In the cup's local coordinate system, it is not rotating, but as the cross on the right rotates around its Z axis, it causes the cup to rotate and revolve. In real animations, it will be much easier when the character holding the cup rotates, the cup changes its position respectively.
::图1b中,茶杯是右侧坐标十字的子物体.该十字本身是无形父母的子物体. (它既是父母又是孩子.) 在杯子的局部坐标系统中,它不是在旋转,但当右侧的十字绕着它的Z轴旋转时,它会使杯子旋转和旋转.在真实动画中,当持杯子的角色旋转时,杯子会更容易,杯子会分别改变位置.

View coordinates

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Figure 2:  View coordinates and Projection Plane

Taking the viewer of the scene into consideration, there is another coordinate space: the view coordinates. In  Fig. 2  the viewer is symbolized by the camera. The Z axis of the view coordinates always points directly to the viewer in orthographic projection. The X axis points to the right, the Y axis points upwards ( Fig. 3 ).
::视图中的视角坐标是指视角坐标的位置.在图2中,视角坐标的Z轴总是指向视角的直角.X轴指向右,Y轴指向上 (图3).在图3中,视角坐标的Z轴指向视角的位置.在图3中,视角坐标的Z轴指向视角的位置.在图3中,视角坐标的Z轴指向视角的位置.在图3中,视角坐标的位置指向视角的位置.在图3中,视角坐标的位置指向视角的位置.在图4中,视角坐标的位置指向视角的位置.

Figure 3:  View coordinates in viewing direction

In fact you always work in view coordinates if you don't set it any other way*. This is particularly useful if you have aligned your view prior to modeling something, e.g. if an object has a slanted roof and you want to create a window to fit in that roof, it would be very complicated to build the window aligned to the local coordinate system of the object, but if you first align your view to the slanted roof, you can easily work in that view coordinate system.
::事实上,如果你没有设置其他方式,你总是使用视图坐标工作.* 这尤其有用,如果你在建模某物之前已经对视图进行了对齐,例如,如果一个物体有斜顶,你想创建一个窗口,以适应该屋顶,将很复杂地构建窗口对齐到物体的本地坐标系统,但如果你首先对视图对齐到斜顶,你可以很容易地在该视图坐标系统中工作.

(* In the Blender 2.6 series, the default has been changed to global coordinates. View coordinates remain as an option.)
:伤心* 在Blender 2.6系列中,默认已被更改为全局坐标. 视图坐标仍然是可选的.)

If you work in one of the three standard views (Front/Top/Side) the alignment of the view coordinates fits the global coordinates. Therefore, it is quite natural to model in one of the standard views and many people find this the best way to model.
::如果您在三个标准视图 (前方/上方/侧面) 中之一工作,则视图坐标的对齐符合全局坐标.因此,在标准视图中的一个中建模是很自然的,许多人认为这是建模的最佳方式.

Normal coordinates

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Figure 4:  Normal coordinate spaces for faces. The normal is shown in blue.

Although Blender is a 3D program, only objects' faces are visible. The orientation of the faces is important for many reasons. For example, in our daily lives it seems quite obvious that a book lies flat on a table. This requires the surface of the table and that of the book to be parallel to each other. If we put a book on a table in a 3D program, there is no mechanism that forces these surfaces to be parallel. The artist needs to ensure that.
::虽然Blender是一个3D程序,但只有对象的面孔是可见的.面孔的方向是重要的,因为许多原因.例如,在我们的日常生活中,很明显,一本书躺在桌子上.这需要桌子的表面和书的平行对方.如果我们把一本书放在桌子上在3D程序,没有机制,迫使这些表面平行.艺术家需要确保.

The orientation of a face can be described with the help of the so-called surface normal. It is always perpendicular to the surface. If several faces are selected, the resulting normal is averaged from the normals of every single face. In  Fig. 4  the normal coordinates of the visible faces are drawn.
::一个面的方向可以用所谓的表面正规来描述.它总是垂直于表面.如果选择多个面,则从每个单一面的正规中平均得出所得到的正规.在图4中,可见面的正规坐标被绘制出来.

This concept can be applied to individual points on the object, even if the points themselves have no orientation. The normal of a point is the average of normals of the adjacent faces.
::这个概念可以应用于对象上的单个点,即使这些点本身没有方向.一个点的正常值是相邻面的正常值的平均值.

UV Coordinates

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In later parts (for example, talking about textures) you will come across coordinates labelled “U” and “V”. These are simply different letters chosen to avoid confusion over “X”, “Y” and “Z”. For example, a raster image is normally laid out on a flat, two-dimensional plane. Each point on the image can be identified by X and Y coordinates. But Blender can take this image and wrap it around the surface of a 3D object as a texture. Points on/in the object have X, Y and Z coordinates. So to avoid confusion, the points on the image are identified using U and V to label their coordinates instead of X and Y. We then refer to “UV mapping” as the process of determining where each (U, V) image point ends up on the (X, Y, Z) object.
::在后面的部分 (例如,谈论纹理) 你会遇到标记为 U 和 V 的坐标.这些只是为了避免混 X, Y 和 Z而选择的不同字母.例如,一个图像通常布置在平面,二维平面上.图像上的每个点可以通过 X 和 Y 坐标识别.但是 Blender 可以将这个图像取并将它包裹在 3D 对象的表面上作为纹理.对象上的/在对象中的点有 X,Y 和 Z 坐标.因此,为了避免混,图像上的点使用 U 和 V 来标记其坐标而不是 X 和 Y.然后我们将UV映射作为确定图像上的每个 (U,V) 点在 (X,Y,Z) 对象的


最后修改: 2025年03月11日 星期二 17:10