LERP Animator

Introduction

The interface

Start on play

Loop

Transforms to act on

Start States

Segments

Last selected state indicator

Workflow

FAQ

Introduction

Many types of animatics in games consists of linear interpolation between positions, rotations and/or scales, executed over a sequence of segments.

Game engines make interpolation easy, but it requires a bit of programming in relation to playback and data management to make it practical to do this for many transforms and segments in a single animatic.

The LERP Animator is a Unity component that let's you take an unlimited number of transforms and run them through an unlimited number of segments of interpolations, all controlled within a single custom inspector. This can replace the need for using third party software to rig and animate , for then to import them as assets, for these kinds of animatics.

Other benefits of LERP Animator:

It let's you preview segment states or play through the animatic live in the editor without starting game play

It makes it easy to set target position and scale data for interpolation, by sampling the data from the scene
Rotation is not as straight forward to deal with as position and scale, as you can't sample the euler angles or quaternion values of an object and expect it to interpolate past 180 degrees around an axis. Default rotation lerping will interpolate the shortest path between two rotations. LERP Animator solves this by manually letting you dial in a rotation offsett from the previous state.
For extra usefullness in game development, it can also fire any kind of events between segments.
Very code friendly. The only need to code is if you want to trigger the animatic any time other than when the game starts and not through an event on another component inspector. This is easily done by getting a reference to the instance and calling the StartSequence() function.

The interface

Start on play

Starts the animatic when you start the game in the scene.

(Note!) Since a transform can be added to several LERP Animators, no action is taken to ensure that transforms are in any particular start states when the game starts or when starting the sequence through code. This is left up to the user.

Loop

Will loop the sequence in both game play mode and while in editor

Transforms to act on

The transforms that can be manipulated in the animatic.

Start States

The starting point of the animatic. Important things to remember:

Adding a transform to the "Transforms to act on" array automatically saves its data to start states

Start states contains the starting point for position, rotation and scale. Since rotation offsets are applied from the start states, saving a new rotation start state by pressing "Sample scene" after adding rotation offsets in segments, will produce different rotation destinations than originally shown. This is not an issue for positions and scales.

Preview applies the stored start states to the transforms.
Sample from scene stores the positions, rotations and scales of the transforms.

Segments

Play plays the sequence in editor from that specific segment and runs to the end of the whole sequence.
Events will make events fire before or after lerping for that segment. Events are only fired during gameplay.
Duration is the time in seconds you want the lerping to last.
Pause after will apply a pause after lerping is done for that segment.
Curve will set the animation curve for that segment. Important to note:

LERP Animator lerps without clamping, so the curve can go above 1 or below 0 along the way in the y axis to make some interesting effects.

The curve must end on 1 in the x-axis. Only set duration via the Duration property.

Rotation offsets lets you dial in rotation offsets for each transform and axis for that segment.

Preview applies the stored segment destination state to the transforms.
Sample from scene stores the positions and scales of the transforms.

Last selected state indicator

The Last selected state indicator shows you which state you last pressed Preview or Sample scene on. This makes it easier to keep track when going between the inspector and the objects in the scene you are manipulating.

Workflow

When adding a new transform to the list of transforms to act on, transform data is sampled into start states (all data), and any existing segments (position and scale).

When adding a new segment, data is also auto sampled into that segment.

This suggests that an efficient work flow would be to:

Set up all the transforms in the desired start states
Add transforms to the list on a LerpAnimator instance.
Alternate between moving the transforms around <----> adding a segment and dial in desired rotation offsets

(Note!) Adding a LERP Animator component to a game object will not automatically add the transform of that object to the list. This is because it is intended to support many transforms. In that case it can be desirable to have it on a top level object with manipulated transforms as children.

(Note!) LERP Animator works with local transform data. If you change the hierarchy of your chosen transform after adding it to a LERP Animator, pressing preview on start states or segments will not yield the same result as before. It is recommended to be done setting up transform hierarchies before adding transforms to LERP Animator.

The position tool handle must be set to “Pivot” when dealing with sub objects to get the gizmo in the center of that object.

The rotation tool handle must be set to “Local” to be able to correctly gage which axis rotation offsets will happen around when dialling in offsets in any segments.

FAQ

Nothing is animating!

Did you actually add the transform to the TransformsToActOn list? Adding the Lerp Animator component won’t add the transform for that object to the list by default. Since Lerp Animator is designed to also work with any number of transforms simultaneously it may be preferred to have a top level object with animated transforms as children.

How do I trigger the animation through code?

Get a reference to the particular LerpAnimator component, and call the public function StartSequence().

Can I have the same transform present in multiple LerpAnimator’s?

Yes you can, but it’s up to you to make sure they aren’t running at the same time during playback.

How do I copy data from one segment to another?

Press Preview on the segment you want to copy from, then press Sample scene on the segment to copy to.

How do I edit existing segments?

Press Preview on the segment, manipulate your transforms, then go back and press Sample scene on segment.

How do I handle several LERP Animator animatics for the same transforms?

Make sure the transforms are in the desired start state for any particular animatic by pressing Preview on a start state or last segment of another.