Shrinkwrap Constraint 缩裹约束¶
缩裹 约束是 缩裹修改器 。它移动自身原点和因此使自身物体位置移到其目标的表面。
这意味着目标 必须 有一个表面。事实上，约束是甚至更具有选择性，因为它只可以使用网格作为目标。因此，缩裹 选项仅显示在 Add Constraint to Active Object(添加约束到活动对象) 菜单，快捷键 Ctrl-Alt-C ，（或相当于它的骨骼），当所选的非激活（活动）对象是一个网格时。
- Target 目标
数据ID 用于选择约束目标，目标 必须 将网格物体， 当它为无(none）时不起作用(红色状态)。
- Distance 距离
This number button controls the offset of the owner from the shrunk computed position on the target's surface.
Shrinkwrap Type 缩裹类型¶
This selector allows you to select which method to use to compute the point on the target's surface to which to translate the owner's origin. You have these options:
Nearest Surface Point 最近的表面点¶
The target's surface point is determined by projecting the owner's origin along a given axis.
- Projection Axis 投影轴
This axis is controlled by the radio buttons that show up when you select this type. This mean the projection axis can only be aligned with one of the three axes, or their opposites. When the projection of the owner's origin along the selected direction does not hit the target's surface, the owner's location is left unchanged.
+X, +Y, +Z, -X, -Y, -Z
- Axis Space 轴空间
Coordinate space in which the axis direction is specified.
- Projection Distance （投影距离）项目距离
Distance cutoff after which projection is assumed to have failed, leaving the location unchanged.
- Face Culling
This radio button allows you to prevent any projection over the "front side" (respectively the "back side") of the target's faces. The "side" of a face is determined by its normal (front being the side "from where" the normal "originates").
Off, Front, Back
- Project Opposite
In addition to the selected projection axis, project in the opposite direction and choose the closest hit.
- Invert Cull
When used with Project Opposite and Face Culling, it inverts the Front or Back cull choice for the opposite direction.
Nearest Vertex 最近的点¶
This method doesn't support the Snap Mode setting described below.
Target Normal Projection¶
This method is similar to Nearest Surface Point, but produces a much smoother projection in return for being significantly slower.
Instead of finding the closest point, it searches for the nearest point that has its interpolated smooth normal pointing towards or away from the original owner position. Non-manifold boundary edges are specially handled as infinitely thin cylinders that emit normals in all perpendicular directions. Ignores flat shading and auto smooth settings.
Most Shrinkwrap types support an additional setting to control how the owner is moved to the target point selected by the methods described above. Some of the choices only differ if Distance is not zero.
- On Surface
The owner location is always changed. The offset is applied along the projection line connecting the original owner location and selected target point towards the original position.
- Outside Surface
Like On Surface, but the offset is always applied towards the outside of the target.
- Above Surface
Like On Surface, but the offset is applied along the smooth normal of the target.
The owner is not moved if it is already inside the target. Offset shrinks the allowed volume towards the inside along the projection line.
The owner is not moved if it is already outside the target. Offset expands the exclusion volume towards the outside along the projection line.
The Inside and Outside options can be used for very crude collision detection. The inside vs outside determination is done based on the target normal and is not always stable near 90 degree and sharper angles in the target mesh.
Align Axis To Normal¶
Whenever Snap Mode is available, it is also possible to align the specified local axis of the object to the smooth normal of the target at the selected point. The axis is selected via radio buttons.
The alignment is performed via smallest rotation, like in Damped Track constraint.