user: How do I use Blend in Blender? Include parameters, examples, warnings and best practices.

assistant: Adjusts the values of the selected keyframes by a certain percentage. Select a blending operator,
move the mouse left or right to adjust the factor, and click `LMB` to confirm
(or `RMB` to cancel).

Several blending operators work based on “neighboring keyframes.” This means that they divide the
selected keyframes into contiguous groups, then reference the unselected keyframes immediately
before and after each group.

### Breakdown

Sets the value of the selected keyframes to an interpolation of their neighbors.

Factor
:   At -1, the keyframes are set to the value of the left neighbor.

    At 1, they’re set to the value of the right neighbor.

    For other factors, they’re set to an interpolation between the two neighbor values,
    with 0 being right in the middle.

### Blend to Neighbor

Moves each selected keyframe towards the value of the left or right neighbor by a certain percentage.

Blend
:   When negative, each keyframe moves *Blend* percent to the value of the left neighbor.

    When positive, they move to the right neighbor.

    When zero, they keep their original values.

### Blend to Default Value

Moves the selected keyframes towards the property’s default value by a certain percentage.

Factor
:   How much to change the keyframes’ values, going from 0 (no change) to 1 (reset to the default value).

### Ease

Makes the selected keyframes follow an S-curve. While the slider is visible (so after activating
the operator but before confirming with `LMB`), you can press `Tab` to toggle which
of the following settings to edit:

Curve Bend
:   A negative value gives more weight to the left side, while a positive value gives more weight
    to the right. A value of 0 results in a balanced curve.

Sharpness
:   A low value results in an almost straight diagonal line, while a high value results in a steep
    rise/drop in the curve.

### Blend Offset

Moves the selected keyframes up or down – all by the same amount – until the first/last one matches
the left/right neighbor.

Offset Factor
:   At -1, the first selected key gets aligned to its left neighbor.

    At 1, the last selected key gets aligned to its right neighbor.

    At 0, nothing changes.

### Blend to Ease

Blends the selected keys to either an “ease in” or an “ease out” curve.

Blend
:   At -1, the keys will follow an “ease in” curve, with small value changes in the beginning
    and large changes towards the end.

    At 1, the keys will follow an “ease out” curve, with large value changes in the beginning
    and small changes towards the end.

    At 0, nothing changes.

### Match Slope

Blends the selected keys towards a straight line going through two keys just outside the current selection.

Factor
:   Negative values use the two keys to the left of the selection.

    Positive values use the keys to the right.

    At zero, nothing changes.

### Push Pull

Moves the selected keys towards, or away from, the straight line going through the first and last
selected key.

Factor
:   At 0, the keys will lie on the straight line.

    At 1, they keep their original values.

    At 2, each key’s value will be twice as far from the straight line as before.

### Shear Keys

Shears the selected keyframes – that is, changes their value by an amount that increases
as they get further away in time from a reference keyframe. By default, this reference keyframe
is the leftmost selected one, but you can instead use the rightmost one by pressing `D`.

Shear Factor
:   How much to shear. Negative values move keyframes downwards, while positive ones move them up.

Direction
:   Whether to use the leftmost or the rightmost selected keyframe as a reference.

### Scale Average

Scales the selected keyframes vertically, using their average value as the pivot.

Factor
:   At 0, the keyframes will all have the average value.

    At 1, they keep their original values.

    At 2, each keyframe’s value will be twice as far from the average as before.

### Scale from Neighbor

Scales the selected keyframes vertically, using a keyframe just outside the selection as
the pivot. By default, this is the neighbor to the left of the selection,
but you can instead use the right one by pressing `D`.

Factor
:   The scale factor to apply.

Reference Key
:   Whether to use the left or right neighbor as the pivot.

### Time Offset

Shifts the values of the selected keyframes so that the resulting F-Curve appears to move in time.
Works best with dense keyframes.

As the curve leaves the selected keyframes’ time range on one end, it wraps back in on the other,
offset vertically so that the ends connect and there is no jump.

Frame Offset
:   By how many frames to shift the F-Curve. The slider is limited to the range -10 … 10,
    but you can type larger numbers too.