# Symmetries

Symmetry entities define planes of symmetry within a model so that morphs can be applied in a symmetric fashion.

Symmetries do not have an active or export state.

There are two basic symmetry groups: reflective and non-reflective. Symmetries can be combined, but you must be careful not to create confusing symmetrical arrangements. Symmetries can also be applied to unconnected domains. In this case, the symmetric handle linking works the same as that for connected domains, but the influences between handles and nodes for non-reflective symmetries do not extend across to all domains.

## Reflective Symmetries

Reflective symmetries link handles in a symmetric fashion so that the movements of one handle will be reflected and applied to the symmetric handles. You can also use reflective symmetries to reflect morphs performed on domains when using the alter dimensions.

Reflective symmetries are one plane, two plane, three plane, and cyclical.
One Plane
A mirror is placed at the origin perpendicular to the selected axis (default = x-axis).
Two Plane
Two mirrors are placed at the origin perpendicular to the selected axis and the subsequent axis (that is x and y, y and z, z and x) (default = x and y-axis).
Three Plane
Three mirrors are placed at the origin perpendicular to all three axes.
Cyclical
Two mirrors are placed along the selected axis (default = z-axis) and running through the origin with a given angle in between that is a factor of 360. The result is a wedge that is reflected a certain number of times about the selected axis.
Reflective symmetries can be defined as either unilateral or multilateral and either approximate or enforced.
Unilateral Symmetries
One side governs the other, but not vice versa.
For example, handles created and morphs applied to handles on the positive side of the symmetry are reflected onto the other side or sides of the symmetry, but handles created or morphs applied to handles on the other side or sides of the symmetry are not reflected.
Multilateral Symmetries
All sides govern all other sides.
For example, a handle created or a morph applied to a handle on any side is reflected to all the other sides.
Approximate Symmetries
Contain handles that are not symmetric to other handles. This option is best for asymmetrical, but similar, domains or for a cyclical symmetry applied to a mesh that sweeps through an arc but not a full circle.
For example, handles created on any side of the symmetry are not reflected to the other sides.
Enforced Symmetries
Cannot contain handles that are not symmetric on all other sides.
For example, handles created or deleted on any side of the symmetry are created or deleted on the other sides so that the symmetry is maintained. When a reflective symmetry is created with the enforced option, additional handles may also be created to meet the enforcement requirements.
Note: Handles created due to the enforced symmetry may not be located on any mesh, however, they will always be assigned to the nearest domain and will affect nodes in that domain.

## Non-Reflective Symmetries

Non-reflective symmetries change the way that handles influence nodes as well as link the symmetric handles so that the movement of one affects the others.

The handles for a domain with non-reflective symmetry will act as if they are the shape of the symmetry type. For instance, a domain with linear symmetry causes handle movements to act on the domain as if the handle was a line in the direction of the x-axis. A domain with circular symmetry causes handle movements to act on the domain as if the handle was a circle centered around the z-axis. The edges of a domain affect how influences between handles and nodes are calculated. Non-reflective symmetries work best for domains that are shaped like the symmetry type and have a regular mesh. For example, a circular symmetry works best for a round domain with a concentric mesh.

Non-reflective symmetries are linear, circular, planar, radial 2D, cylindrical, radial + linear, radial 3D, and spherical.
Linear
Handle acts as a line drawn through the handle location parallel to the selected axis (default = x-axis).
Circular
Handle acts as a circle drawn through the handle position about the selected axis (default = z-axis).
Planar
Handle acts as a plane drawn through the handle location perpendicular to the selected axis (default = x-axis).