# Trajectory Control

## Overview

The Trajectory Control feature allows for precise path creation that characters will follow during motion generation.

## Tool Inputs

<figure><img src="https://3763251240-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F9BAa74uZVvvtnO0Rq9Vh%2Fuploads%2Fgit-blob-19744e587f9ddfe091d12429fa39513ca1d7dd0b%2Ftrajectory-control.png?alt=media" alt=""><figcaption></figcaption></figure>

Inputs:

* **Prompt:** A text prompt describing the motion
* **Walking Styles**: Choose from Forward, Backward, Sideways Left, or Sideways Right. The character will move along the defined trajectory in the selected style.
* **Seed:** A random number used for generating varied outputs with identical inputs. For instance, two generated motions with different seeds, might differ even with the same text prompt, walking style and trajectory.
* **Trajectory**: Press "+" button to generate a new trajectory. Use the dropdown asset picker to utilize an existing one
* **Bindings**: A list of all bindings that contain a Transform Track

## Trajectory Design

You can define the trajectory for you character in 2 ways:

1. **Design your own trajectory:** If you want to design a trajectory on the fly, you can press the "+" button next to the "Trajectory" field, which generates and opens a new Level Sequence at the Sequencer with the SMPL Skeletal Mesh spawned at your current Level. That mesh contains a Transform Track in the Level Sequence with **2 keyframes** at frames 0 and 195 (a straight line by default). Within the Sequencer, you can insert and edit as many keys as necessary to shape the desired trajectory.
2. **Use existing trajectory:** If you already have designed a trajectory in an existing Level Sequence, you can choose it from our asset picker in the Trajectory field. Once you do that, a list will be populated in the "Bindings'' field with all the bindings that contain a Transform Track. You can choose the transform track that has the keys of the desired trajectory.

{% hint style="info" %}
Please note that the system currently considers frames 0 to 195 in the Sequencer, so ensure your trajectory fits within this range
{% endhint %}

{% hint style="info" %}
Our template Level Sequence spawns the SMPL mesh for visual purposes. However, you can use any binding in a Level Sequence that has a [Transform Track](https://docs.unrealengine.com/5.3/en-US/cinematic-transform-and-property-tracks-in-unreal-engine/) and contains Location keys. Taking advantage of the powerful tools of the Sequencer will allow you to design a very detailed trajectory.
{% endhint %}

{% hint style="warning" %}
Avoid editing Rotation keys, as the character's orientation is determined in the output. Additionally, pay close attention when setting the Location keys in time; improper timing can result in unnatural motion due to the calculated speed at which the character moves along the trajectory.
{% endhint %}

Here's a video showcasing how to use the feature:

{% embed url="<https://youtu.be/Lj3FVUwpynk>" %}