******** Children ******** .. admonition:: Reference :class: refbox :Panel: :menuselection:`Particle System --> Children` *Children* are *Hair* and *Keyed* particles assigned subparticles. They make it possible to work primarily with a relatively low amount of Parent particles, for whom the physics are calculated. The children are then aligned to their parents. Without recalculating the physics the number and visualization of the children can be changed. Children can be emitted from particles or from faces (with some different options). Emission from *Faces* has some advantages, especially the distribution is more even on each face (which makes it better suitable for fur and the like). However, children from particles follow their parents better, e.g. if you have a soft body animation and do not want the hair to penetrate the emitting mesh. But see also our manual page about :doc:`Hair `. If you turn on children the parents are no longer rendered (which makes sense because the shape of the children may be quite different from that of their parents). If you want to see the parents additionally turn on the *Parents* button in the *Visualization* panel. Children carry the same material as their parents and are colored according to the exact place from where they are emitted (so all children may have different color or other attributes). The possible options depend from the type of particle system, and if you work with *Children from faces* or *Children from particles*. We do not show every possible combination, only the settings for a *Hair* particle system. Common Options ============== Child Type None No children are generated. Simple Children are emitted from the parent position. Interpolated Children are emitted between the *Parent* particles on the faces of a mesh. They interpolate between adjacent parents. This is especially useful for fur, because you can achieve an even distribution. Some of the children can become virtual parents, which are influencing other particles nearby. Display Amount The number of children in the 3D View. Render Amount The number of children to be rendered. Length Length of child paths. Threshold Amount of particles left untouched by child path length. Seed Offset in the random number table for child particles, to get a different randomized result. Clumping -------- .. admonition:: Reference :class: refbox :Panel: :menuselection:`Particle System --> Children --> Clumping` Use Clump Curve Use :ref:`ui-curve-widget` instead of parameters. Clump Clumping amount along child strands. The children may meet at their tip (1.0) or start together at their root (-1.0). Shape Form of *Clump*. Either inverse parabolic (0.99) or exponentially (-0.99). Twist Todo. Use Twist Curve Todo. Clump Noise ^^^^^^^^^^^ Creates random clumps around the parent hair. Clump Noise Size The size of the clumps. Roughness --------- .. admonition:: Reference :class: refbox :Panel: :menuselection:`Particle System --> Children --> Roughness` Use Roughness Curve Use :ref:`ui-curve-widget` instead of parameters. Uniform, Size It is based on children location so it varies the paths in a similar way when the children are near. Endpoint, Shape "Rough End" randomizes path ends (a bit like random negative clumping). Shape may be varied from <1 (parabolic) to 10.0 (hyperbolic). Random, Size, Threshold It is based on a random vector so it is not the same for nearby children. The threshold can be specified to apply this to only a part of children. This is useful for creating a few stray children that will not do what others do. Kink ---- .. admonition:: Reference :class: refbox :Panel: :menuselection:`Particle System --> Children --> Kink` .. _fig-particle-child-kink: .. figure:: /images/physics_particles_emitter_children_kink.png Child particles with Kink. From left to right: Curl, Radial, Wave, Braid, Spiral. With *Kink* you can rotate the children around the parent. See Fig. :ref:`fig-particle-child-kink` above picture for the different types of *Kink*. Kink Type Nothing Deactivated. Curl Children grow in a spiral around the parent hairs. Radial Children form around the parent a wave shape that passes through the parent hair. Wave Children form a wave, all in the same direction. Braid Children braid themselves around the parent hair. Spiral Generates a spiral at the end of each hair. Radius, Resolution Define the overall size. Shape Makes a the spiral grow in- or outward. .. note:: Alignment Limitations When hair is pointing straight up (along the chosen spiral axis, default Z), spirals may not show up! This is a limitation of the projection method used. Giving a slight tilt or random orientation to hairs fixes this. Amplitude The amplitude of the offset. Clump How much clump effects kink amplitude. Flatness How flat the hairs are. Frequency The frequency of the offset (1/total length). The higher the frequency the more rotations are done. Shape Where the rotation starts (offset of rotation). Simple ====== Size Only for *Emitter*. A multiplier for children size. Random Size Random variation to the size of child particles. Radius The radius in which the children are distributed around their parents. This is 3D, so children may be emitted higher or lower than their parents. Roundness The roundness of the children around their parents. Either in a sphere (1.0) or in-plane (0.0). Interpolated ============ Virtual Parents Relative amount of virtual parents. Long Hair Calculate children that suit long hair well. Parting ------- TODO. Example ======= .. figure:: /images/physics_particles_emitter_children_round-clump.png From left to right: Round: 0.0, Round: 1.0, Clump: 1.0, Clump: -1.0, Shape: -0.99.