FK Animation

FK (Forward Kinematics) Animation allows users to manually create and customize character animations by adjusting individual body parts over time. It provides complete control over character movement through keyframes and transform properties.

Important: When a predefined Custom Animation is active in the workspace, the animation itself cannot be edited. Users can only preview and use the animation. To create or modify animation movements, a new FK animation must be created or remove the used custom animation from the timeline.

Opening FK Animation

Select a character or vehicle inside STPro Animator.
Navigate to the Animations panel.
In custom animation click on Add New +.
The FK Animation workspace will open.

The workspace consists of:

Animation Panel
Layers Panel
Audio Panel
Canvas Area
Timeline
Transform Panel

FK Animation Workspace

Left Panel

The Left Panel contains the primary tools used to create, edit, and manage FK animations.

The available options inside the panel are generated dynamically based on the currently selected character, vehicle, or asset.

The panel contains three tabs:

Animations
Layers
Audio

Animations

The Animations tab displays all animation categories available for the selected asset.

FK Animation supports both character and vehicle animation workflows. The available animation categories depend entirely on the currently selected asset.

Examples of available categories include:

Walking
Talking
Expression
Hands
Idle
Sleeping
Scared
General
Vehicle Animations
Custom

Each category contains pre-built animations designed for specific actions and behaviors.

Animation Categories

Users can:

Browse animation categories
Preview available animations
Apply animations to the selected asset
Combine multiple animations
Create and manage custom animations

Custom Animations

The Custom category displays animations created by the user.

Only custom animations associated with the currently selected character, vehicle, or pose will appear in the Custom category.

For example:

Character custom animations are visible only for that character.
Vehicle custom animations are visible only for that vehicle.
Pose-specific custom animations are visible only when the corresponding pose is selected.

This ensures users only see animations that are compatible with the currently selected asset.

Layers

The Layers tab displays all editable layers, bones, slots, attachments, and rig components available for the selected asset.

The contents of the Layers panel change dynamically depending on the selected character or vehicle.

Examples for character assets include:

Body
Head
Eyes
Mouth
Arms
Legs
Hair
Clothing
Accessories
Attachments

Layers Panel

Examples for vehicle assets include:

Front Glass
Back Glass
Windshield Wiper
Head Light
Left Indicator
Right Indicator
Wheel
Vehicle Attachments

Users can:

Select individual layers
Select multiple layers
Expand and collapse layer groups
Access editable bones
Control attachments
Create custom animations

The Layers panel provides direct access to all editable parts of the selected asset.

Select All Layers

The Select All Layers option automatically selects all available editable layers and bones for the currently selected asset.

This feature is useful when:

Reviewing the complete rig structure
Managing large characters
Managing complex vehicles
Quickly viewing all editable components

Once enabled, all available layers become visible and accessible for editing.

Users can then select a specific bone, slot, or attachment and apply animation changes as needed.

Select All Layers

Audio

The Audio tab allows users to add, preview, and synchronize audio with animations.

Audio can be added from:

My Assets
Previously uploaded audio files
Voiceover recordings
Narration tracks
Sound effects
Background music

Supported formats include:

Users can:

Import audio into FK Animation
Select audio from My Assets
Preview audio before use
Synchronize speech with animation
Create lip-sync animations
Align gestures with dialogue timing

Audio Tab

Adding Audio from My Assets

Audio files stored inside My Assets → MP3 / WAV can be used directly inside FK Animation.

To use audio:

Open the Audio tab.
Select an audio file.
Load the audio into the workspace.
Preview the audio.
Synchronize animation timing with the audio.

This allows audio assets to be reused across multiple projects without re-uploading files.

Voice Timing Editor

When audio is selected, the Voice Timing Editor allows users to synchronize animation timing with speech.

The editor provides:

Audio waveform visualization
Playback controls
Audio duration information
Start and end markers
Lip-sync options

Users can drag the waveform handles to select the exact audio segment used during animation creation.

This helps animators create more accurate dialogue timing and character performance.

Auto Lip Sync

The Apply Auto Lip Sync option automatically generates lip-sync information from the selected audio segment.

When enabled:

Speech timing is analyzed automatically
Mouth animation is generated
Lip-sync data is applied to supported character rigs
Manual lip-sync work is reduced

This helps accelerate dialogue animation workflows.

Lips Sync

Audio Reference Mode

Audio used inside FK Animation serves as animation reference audio.

Important:

Audio timing is used during animation creation.
Reference audio is not automatically added to the final project timeline.
Audio must be added separately on the main Animator timeline if it should be included in the final exported video.

This workflow provides accurate animation timing while allowing independent audio management.

Dynamic Asset Behavior

FK Animation automatically adapts to the selected asset.

Available functionality depends on whether the user is animating:

Human characters
Vehicles
Other supported rigged assets

The following elements are generated dynamically:

Animation categories
Layers
Bones
Slots
Attachments
Timeline tracks
Transform controls

Different assets expose different animation capabilities based on their rig structure.

For example:

Human Characters

Human characters may provide:

Facial controls
Body controls
Arm controls
Leg controls
Hand controls
Expression attachments
Clothing attachments

Vehicles

Vehicles may provide:

Wheel controls
Wiper controls
Glass controls
Indicator controls
Headlight controls
Vehicle attachments

Only controls supported by the selected asset are displayed.

Canvas Area

The Canvas Area displays the currently selected character or vehicle.

This workspace is used for posing, editing, and previewing animations.

Users can:

Select bones
Select slots
Select attachments
Adjust poses
Preview movement
Create keyframes

Green control points indicate editable rig controls.

Bone and attachment controls vary depending on the selected asset.

Canvas Controls

Timeline Behavior

The timeline displays animation tracks for the currently selected layer, bone, slot, or attachment.

When a layer is selected, the timeline automatically displays all supported tracks for that element.

Available tracks may include:

Position
Rotation
Scale
Attachment

Only supported tracks are shown.

Timeline Tracks

Examples include:

Wheels using rotation animation
Indicators using attachment switching
Glass components using position, rotation, scale, or attachment tracks

The timeline automatically updates whenever a different layer is selected.

This allows users to focus on the controls relevant to the currently selected component.

Transform Properties Panel

The Transform Properties Panel displays editing controls for the currently selected layer, bone, slot, or attachment.

Available controls are generated dynamically based on the selected asset and supported properties.

Available transform controls may include:

Transform Panel

Rotation

Controls the rotation angle of the selected element.

Options include:

Keyframe toggle
Step value
Rotation slider
Rotation input field

Scale

Controls object scaling.

Options include:

Scale X
Scale Y
Link X/Y scaling
Keyframe support

When Link X/Y is enabled, both axes scale proportionally.

Position

Controls object position.

Options include:

X Position
Y Position
Step Value
Keyframe support

Attachment

Controls attachment switching for supported assets.

Attachment tracks can be used to change:

Facial expressions
Vehicle states
Accessory variations
Asset-specific attachments

Flip

Used to mirror supported objects.

Options include:

Left
Right

Not every asset supports every transform type.

For example:

Wheels may support rotation and position.
Windshield wipers may primarily support rotation.
Facial attachments may support attachment switching.
Character bones may support position, rotation, and scale.

Only valid controls are displayed for the selected layer.

Working with Keyframes

Keyframes store transformation values at specific timeline positions.

Supported keyframe types:

Position Keyframes
Rotation Keyframes
Scale Keyframes

Creating a Keyframe

Select a bone.
Move the timeline playhead.
Modify a transform property.
Enable the key option.
A keyframe is created automatically.

Timeline Behavior

The timeline displays animation tracks for the currently selected layer, bone, slot, or attachment.

When a layer is selected following transform properties become available:

Position
Rotation
Scale
Attachment slot when supported

Multiple Key Selection

Users can select multiple keyframes simultaneously.

Benefits:

Move multiple keys together.
Delete multiple keys.
Adjust timing of multiple keys.
Organize animation sequences faster.

Enable the Select Multiple Keys option above the timeline.

Multiple Key Selection

Layer Selection

Select All Layers

Users can select all character layers from the Layers panel.

Useful when:

Applying global changes
Reviewing rig structure
Managing large characters

Select All Layers

Deselect All Layers

Users can also deselect all layers to focus on specific body parts.

Select All Layers

Reset Function

The Reset button restores the selected animation to its default state.

Use Reset when:

Incorrect modifications have been made.
A pose needs to be restored.
Testing different animation variations.

Reset only restores the current animation state and does not automatically save changes.

Save Function

After editing an FK animation:

Click Save.
The animation changes are stored.
The updated animation becomes available for future use.

Auto Save Behavior

FK Animation does not support automatic saving.

Users must manually save their work.

Unsaved changes will be lost if the workspace is closed or refreshed.

Custom Animation Restrictions

When a Custom Animation is active in the workspace:

Animation movements cannot be edited.
Existing keyframes cannot be modified.
New keyframes cannot be added.
Bone transformations are locked.
Timeline editing is disabled.

Users can:

Preview the animation.
Apply the animation to a character.
Use the animation within projects.

Best Practices

Save frequently while animating.
Use meaningful animation names.
Organize animations by category.
Use multiple key selection for faster editing.
Review poses before exporting.
Use Reset when testing different movement variations.
Keep custom animations finalized before applying them to projects.

Summary

FK Animation provides precise control over character motion through keyframes, transform properties, and bone-based editing tools. Users can animate individual body parts using Position, Rotation, Scale, and Attachment tracks while managing layers and timeline data efficiently. Custom animations can be used within projects, but active custom animations remain locked from further editing to preserve animation integrity.

Next Step

Continue to the next section to learn about:

Adding props to a scene
Managing the Props panel
Positioning and transforming props
Attaching props to character slots
Animating props using keyframes
Organizing prop layers