Grain Source geometry node
谷物来源 几何体节点

Generates particles to be used as sources in a particle-based grain simulation.
生成粒子，以便在基于粒子的颗粒模拟中用作源。

The Grain Source SOP generates emission particles suitable for the POP Grains particle solver.
Grain Source SOP 生成适合 POP Grains 粒子求解器的发射粒子。

Parameters   参数

Particle Type  粒子类型

The type of particle to generate, either Grain or Fluid.
要生成的粒子类型，可以是 颗粒（Grain） 或 流体（Fluid）。

Mode  模式

How to generate the particles.
如何生成粒子。

Solid   固体

Fills the volume of the input with particles.
用粒子填充输入的体积。

Sheet   表

Scatters particles along the surface of the input.
沿着输入表面散射粒子。

Strand   链

Scatters particles along the edges of the input.
沿输入的边缘散射粒子。

Source Type  源类型

When in Solid Mode, this provides a hint of how to interpret the source.
在固体模式下 ，这提供了如何解释源的提示。

Auto-Detect   自动检测

If the input is a single volume primitive, the Fog or SDF method will be used depending whether the volume primitive has the SDF flag set.
如果输入是单个体积基元，则将使用 Fog 或 SDF 方法，具体取决于体积基元是否设置了 SDF 标志。

Geometry   几何学

The input is treated as a closed manifold surface.
输入被视为闭合流形曲面。

Fog   雾

The first volume of the input is treated as a fog volume. Voxels with a 1 value will have points, those with 0 will not have points.
输入的第一个体积被视为雾体积。值为 1 的体素将有点，0 的体素将没有点。

Signed Distance Field   有符号距离场

The first volume of the input is treated as a signed distance field. Voxels with negative values will have points, those with positive values will not.
输入的第一个体积块被视为有符号距离字段。负值的体素将有点，而具有正值的体素则没有。

Construction Method  施工方法

The method used for generating points.
用于生成点的方法。

Dense Grid   密集网格

Creates points inside the entire bounding box of the input, then removes those outside the volume. This method is efficient for inputs that are close to axis-aligned boxes, but can be slow and memory inefficient for more sparse configurations. This method also provides backwards compatibility for files created prior to Houdini 14.5.
在输入的整个边界框内创建点，然后删除体积外的点。此方法对于接近轴对齐框的输入有效，但对于更稀疏的配置可能会很慢且内存效率低下。此方法还为 Houdini 14.5 之前创建的文件提供了向后兼容性。

Sparse Volume   稀疏体积（Sparse Volume）

Creates points only in the active voxels of the input volume if they also lie inside the bounding volume. This method can handle very sparse configurations where the input objects are distributed across space and do not fit well into an axis-aligned bounding box. Because a sparse volume is required, this method creates an OpenVDB volume of the input internally.
仅在输入体积的活动体素中创建点，如果这些点也位于边界体积内。此方法可以处理非常稀疏的配置，其中输入对象分布在空间中，并且不能很好地适应轴对齐的边界框。由于需要稀疏卷，因此此方法在内部创建输入的 OpenVDB 卷 。

Point Separation  点分离

The smallest distance between any two of the generated points in the initial configuration.
初始配置中任意两个生成点之间的最小距离。

Because refers to a radius, the resulting will be half of this to make room for two radii between each particle.
因为指的是半径，所以结果将是半径的一半，以便在每个粒子之间腾出两个半径的空间。pscalepscale

Note  注意

If you halve the point separation, you get eight times the points.
如果将分差减半，则获得八倍的分。

Packing Density  填料密度

Allows for over packing of the input geometry. This is useful if explicit constraints are present as it gives more collision points and reduces the ability of particles to tunnel between each other. However, it means that the particles will be packed too close together, so if breaking occurs they will gain significant energy when they detach.
允许输入几何体的过度打包。如果存在显式约束，这很有用，因为它提供了更多的碰撞点并降低了粒子之间隧道的能力。然而，这意味着颗粒会靠得太近，因此如果发生断裂，它们在分离时会获得大量能量。

The density is measured along a single axis. Thus a density of with Solid mode will generate 8 times the particles, in Sheet mode 4 times the particles, and in Strand mode 2 times the particles.
密度是沿单个轴测量的。因此，在“实体”模式下，密度将生成 8 倍的粒子，在“片状”模式下生成 4 倍的粒子，在“股线”模式下生成 2 倍的粒子。2

Source Offset  源偏移（Source Offset）

Offsets the input surface by a multiple of pscale. Positive values dilate, negative values erode. The default of -1 erodes the volume by pscale so that particles and their radii end up inside the volume.
将输入表面偏移 pscale 的倍数。正值膨胀，负值侵蚀。默认值 -1 通过 pscale 侵蚀体积，以便粒子及其半径最终进入体积内。

Grid Offset  网格偏移（Grid Offset）

The offset used for building the initial dense packed grid of particles. This can be offset to ensure your initial particles are precisely aligned with a ground plane, for example.
用于构建初始密集粒子网格的偏移量。例如，可以对其进行偏移，以确保初始粒子与地平面精确对齐。

Seed  种子

Scattering, jittering, and randomizing the sizes of the particles use this as the seed. Changing it gives different random distributions.
散射、抖动和随机化粒子的大小都将其用作种子。改变它会给出不同的随机分布。

Uniform Radius  均匀半径（Uniform Radius）

If all particles have the same size, many optimizations can be performed later in the simulation. However, it may be worth the expense to break up the uniform look of the particles. This enables the particles to be non-uniform in size.
如果所有粒子的大小相同，则可以在模拟的后期执行许多优化。然而，破坏颗粒的均匀外观可能是值得的。这使得颗粒的大小不均匀。

Random Volume  随机体积

Controls the range of random particle sizes. The randomization occurs over the volume, not the radius, giving a better distribution.
控制随机粒径的范围。随机化发生在体积上，而不是半径上，从而提供更好的分布。

Jitter Scale  抖动尺度

Controls jittering of point positions. To avoid explosions on the first frame, it is important for the relaxation to be run if jittering is on.
控制点位置的抖动。为了避免在第一帧上发生爆炸，如果抖动打开，则运行弛豫非常重要。

Because relaxation can never accurately separate all particles, note that the final will be reduced to minimize overlap.
由于松弛永远无法准确分离所有粒子，因此请注意，最终粒子将减少以尽量减少重叠。pscale

Dither Surface  抖动曲面

If a uniform lattice of points is being built, then the surface layer will exhibit terracing as points cross the boundary. This dithers the points, comparing the distance to the cut-off threshold with a random number to see if the point should be kept. This causes points to be kept outside of the threshold, as it expands half a grid scale in both directions. Turning this on will result in a more randomized surface layer.
如果正在构建一个均匀的点晶格，则当点穿过边界时，表面层将表现出梯田。这会抖动点，将到截止阈值的距离与随机数进行比较，以查看是否应保留该点。这会导致点保持在阈值之外，因为它会在两个方向上扩展半个网格比例。启用此功能将导致更随机的表面层。

Dither Normal  抖动法线

Often an object has one face that is free, and the other faces are constrained by collisions. If you don’t want to dither the colliding faces (as particles may be generated outside of the collision range, or holes made that will collapse) you can use this normal and the angle to specify which regions of the source are available for dithering. The geometric normal of the SDF built from the surface is used, not any normal attribute on the incoming geometry.
通常，一个对象有一个面是自由的，而其他面则受碰撞约束。如果不想抖动碰撞面（因为粒子可能会在碰撞范围之外生成，或者形成的孔会塌陷），则可以使用此法线和角度来指定源的哪些区域可用于抖动。使用从曲面构建的 SDF 的几何法线，而不是传入几何体上的任何法线属性。

Dither Angle  抖动角度

How many degrees away from the dither normal is eligible for dithering. Setting this value to 180 will cause all faces to be dithered.
距抖动法线多少度才有资格进行抖动。将此值设置为 180 将导致所有面都抖动。

Compute Mass  计算质量

Adds a attribute computed from the final particle , important if the particles are varying in size. The value is the density measured as kg/m^3. 1000 corresponds to water.masspscale
添加从最终粒子计算的属性，如果粒子大小不同，则很重要。该值是测量为 kg/m^3 的密度。1000 对应于水。 质量 pscale

Relax Iterations  放松迭代

If jittering or non-uniform sizes are chosen, the default arrangement of particles will overlap, triggering explosions. This runs a pre-pass to try to move the particles without leaving the selected volume.
如果选择抖动或不均匀大小，粒子的默认排列将重叠，从而触发爆炸。这将运行一个预通道，以尝试在不离开选定体积的情况下移动粒子。

In Sheet mode, this corresponds to the Scatter SOP parameter of the same name.
在 Sheet 模式下，这对应于同名的 Scatter SOP 参数。

Error Threshold  错误阈值

If overlap falls below this ratio, the relaxation can be terminated early. 0.05 corresponds to a 5% overlap.
如果重叠低于此比率，则可以提前终止松弛。0.05 对应于 5% 的重叠。

Adjust Radius to Avoid Overlap
调整半径以避免重叠

After relaxation is complete, there may still be overlap between particles. This will cause the particles to explode outwards on the first few frames. To avoid this, this option scales the particles down by their overlap amount to ensure they are no longer overlapping. If Uniform Radius is turned on, they are all reduced equally, otherwise each is only reduced by what is required to stop it from overlapping its neighbor. However, since this opens more space, the particles probably will settle to a smaller volume.
弛豫完成后，粒子之间可能仍存在重叠。这将导致粒子在前几帧向外爆炸。为避免这种情况，此选项会按粒子的重叠量缩小粒子，以确保它们不再重叠。如果启用了 均匀半径（Uniform Radius）， 则它们都会平均减少，否则每个半径只会减少阻止其与相邻重叠所需的值。然而，由于这打开了更多的空间，粒子可能会沉降到更小的体积。

Explicit Constraints   显式约束

Create  创造

Adds poly lines between any particles that overlap. This can be used by the grain pop as constraints.
在任何重叠的粒子之间添加多段线。这可以被颗粒弹出用作约束。

Strength  强度

How strong to make the constraints. This controls the threshold at which they break if breaking is enabled. It adds a primitive attribute that can be altered with other tools before or during the simulation.strength
约束有多强。如果启用了中断，这将控制它们中断的阈值。它添加了一个基元属性，可以在模拟之前或模拟期间使用其他工具进行更改。 强度

Search Radius  搜索半径

How far, compared to to attach neighboring points. Because explicitly constrained points do not collide with each other, this should be at least .pscalepscale
多远，与附加相邻点相比。因为显式约束的点不会相互碰撞，所以这应该至少是 。pscalepscale

Always Show Points  始终显示点

Normal points that are part of polygons are not drawn. This means the sprite display of the spheres for the points will not be drawn when they have constraints. This sets a detail attribute that overrides this, causing all points to be drawn even if they are part of primitives or constraints.
不绘制属于面的法线点。这意味着当点的球体具有约束时，将不会绘制球体的精灵显示。这将设置一个覆盖此属性的细节属性，从而导致绘制所有点，即使它们是图元或约束的一部分。