Table of Contents

Sample Blendspace 1D Node

The Sample Blendspace 1D node is used to linearly interpolate between a fixed set of animations.

Every animation clip is assigned a position value in 1D space. The Lerp input pin value determines how to interpolate those clips. The output pose will be either exactly one of those clips, or a mix between two clips, but never more than that.

So if one clip is placed at position 0 and another at position 1, you can fade from the first clip to the second by passing in a lerp value between 0 and 1.

The length of each clip may be different, however, the lookup positions across all clips are synchronized. That means if two clips are being mixed, and the first clip is sampled right at its middle, then the second clip will also be sampled at its middle, even if this is a completely different time offset (say 1 second versus 1.5 seconds). At which speed to move the sample position forwards, is determined by the length of the two animation clips that the lerp value is closest to.

This node is useful if you have an action that can be done at different speeds and you want to cover all possible speeds with just a few different animation clips. The most intuitive example is a walk/run motion. You only need two animation clips, one for slow walking and one for fast running, and this node allows you to generate any speed in between through interpolation.

For this to work, all animation clips have to follow the rule that they do the same motion at the same relative time offset. So in the case of a walk/run motion, both clips have to start with the same foot forwards, then move the other foot and finally move the first foot again, such that the animation is looped. The clips can have different lengths, though, so the run clip might be shorter than the walk clip (and therefore faster).

In the video above you can see such a transition in action. The lerp input value is varyied to demonstrate how the resulting interpolated animation looks. Here the node also has an idle and a walk backward clip, so it can interpolate between even more states.

Node Properties

Most node properties are the same as on the sample clip node.

  • Clips: A list of animation clips between which this animation node will interpolate. The node will only ever sample the two clips whose Position values are closest the the value provided through the Lerp input pin. Additionally, the playback speed for each clip may be tweaked.

Input Pins

Most input pin properties are the same as on the sample clip node.

  • Lerp: This value determines which animation clips get mixed together. If the lerp value is in between two Position values of two clips, the output pose will be the linear interpolation of those two clips. If the lerp value is lower than the lowest Position value or higher than the highest, the output will be exactly that animation clip (there will be no extrapolation).

Output Pins

Most output pin properties are the same as on the sample clip node.

See Also