The options below are common to both 1D and 2D blending.
You can alter the “natural” speed of animation clips with the animation speed number fields (the columns with a clock icon). For example, you can double the speed of a walk clip by specifying a value of 2.0. The Adjust Time Scale > Homogeneous Speed button rescales the speed of the clips so that they correspond with the chosen minimum and maximum values of the parameter but keep the same relative speed they initially had.
Note that the Adjust Time Scale drop-down is only available if all the motions are Animation ClipsAnimation data that can be used for animated characters or simple animations. It is a simple “unit” piece of motion, such as (one specific instance of) “Idle”, “Walk” or “Run”. More info
See in Glossary and not child Blend Trees.
Enable the Mirror checkbox to mirror any humanoid AnimationAn animation using humanoid skeletons. Humanoid models generally have the same basic structure, representing the major articulate parts of the body, head and limbs. This makes it easy to map animations from one humanoid skeleton to another, allowing retargeting and inverse kinematics. More info
See in Glossary Clip in the motions list. Mirroring uses the same animation as its unmirrored original without doubling the memory and space.
However, mirroring an animation in a blend tree does not create a fully symmetrical animation. Unity automatically adds offsets to ensure that run cycles, walk cycles, and animations such as footsteps are blended correctly with other animation clips and blend trees. For example, if your blend tree has a humanoid running left, and you enable Mirror to switch the humanoid to run right, the foot cycles need to match so that the left foot touches the ground at the same time. This ensures that the mirrored Blend tree correctly blends with surrounding clips and other blend trees that have not been mirrored.