Documentation: Replicated Traversal System

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Replicated Traversal System

Traversal

Aurora Devs

Traversal

Traversal Types

Traversal Types

Type

Description

Hurdle

Jumping over and past an obstacle to a valid location.

Vault

Hurdle when there is no valid landing position. Like jumping out of a window.

Mantle

Climbing/mantling to the top of an obstacle.

Gap Jump

Jumping from one platform to another when there’s a gap in between.

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Settings

Settings

Detail Name

Description

Trace Object Types

Types of objects we can traverse.

Min Distance from Obstacle

Minimum distance from an obstacle to be able to traverse it. This is further scaled with the velocity of the character.

Max Distance from Obstacle

Maximum distance from an obstacle to be able to traverse it. This is further scaled with the velocity of the character.

Min Height Trace

Height at which we start tracing for the height of the obstacle we’re trying to traverse.

Max Height Trace

Height at which we stop tracing for the height of the obstacle we’re trying to traverse. This should be superior to all the heights in the chooser table.

Min Length Trace

Distance forward at which we start tracing for the length/depth of the obstacle we’re trying to traverse.

Max Length Trace

Distance forward at which we stop tracing for the length/depth of the obstacle we’re trying to traverse. This should be superior to all the lengths in the chooser table.

Min Gap Length Trace

Distance forward at which we start tracing for the gap we’re trying to jump over.

Max Gap Length Trace

Distance forward at which we stop tracing for the gap we’re trying to jump over.

Auto Traverse on Impact

Whether character should automatically try to traverse an obstacle if they collide with it while falling. This usually done for mantling only.

Right Foot Bone Name

The name of the right foot bone of the character, usually foot_r.

Left Foot Bone Name

The name of the right foot bone of the character, usually foot_l.

Ignored Actor Tag

Actors with this tag will not be traversed even if detected.

Use Motion Matching

Whether your character uses motion matching, in which case we try to find the best pose in the best animation from the traversal pose database for each traversal.

Pose History Name

The tag of the PoseHistory node in your Animation Blueprint.

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Chooser Table

What are Chooser Tables?

Chooser Tables enable dynamic selection of the appropriate animation based on traversal type (e.g., climbing, jumping) and obstacle dimensions (height, length). This ensures that the character's movements are contextually accurate and visually seamless.

How Chooser Tables Work

Chooser Tables function by mapping each traversal type and obstacle dimension to specific animation montages. During gameplay, when a traversal action is triggered, the plugin references the Chooser Table to select the correct animation. This dynamic selection ensures that the character performs the appropriate animation for each traversal type and obstacle size, enhancing the realism and fluidity of character movements.

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Nested Choosers for each Traversal Type

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Chooser for the Hurdle type. Each animation is associated with specific properties.

Motion Warping

Motion Warping is a feature where you can dynamically adjust a character's root motion to align to targets. This document will show you how to create the Motion Warping logic in your character blueprint, assign Motion Warping windows within animation montages, and link them to named positions.

You can read about it more

here⁠

We use motion warping to align the character to the obstacles they’re trying to traverse which allows dynamic traversal of any obstacle.

Target Names

Target Names

Named Transform

Description

Apex Near

The transform of the nearest ledge on the obstacle we’re trying to traverse.

Apex Far

The transform of the furthest ledge on the obstacle we’re trying to traverse. For Mantling, this isn’t used. For Gap Jumps, this is the nearest edge on the platform we’re trying to jump to.

Landing

The landing position after the obstacle. This is only used for Hurdling.

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Interaction Bone

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Animation Example with authored Interaction bone

The UE5 Mannequin by default has an interaction bone which isn’t set against the mesh. Each animation used animates the position of this bone to where the nearest edge of the obstacle would be (Apex Near).

Motion Warping adjusts the character so that its interaction bone is aligned to the edge of the obstacle, which allows for smooth traversal without clipping.

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If we weren’t to use this bone, the motion warping would try to align the root of the character to the edge, which would make mesh clip with the obstacle.

Urgent Traversal

When we don’t use motion matching, we encounter a problem that would force us to crop most animations, since they have run/walk cycles at the beginning of the animations. This means that the character would play the animation, which makes them run into the obstacle before traversing it.

While a simple solution could be to crop the animation, that early animation data is useful for users who prefer Motion Matching. Thus, we instead opted for Montage sections.

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Sections of a traversal montage

We add an “Urgent” section in the montage right before the action starts (right before the Motion Warping notify). This allows us to skip right to the action of the animation when we need to.

This is especially useful when the character’s falling and wants to climb an obstacle on the way.

Early Blend Out Notifies

The traversal animation montages include an anim notify state at the end to handle early blend outs based on the chosen blend out condition: Forced, With Movement Input, or If Falling. This feature ensures that the animation transitions smoothly and appropriately according to the character's state.

If the blend out condition is Forced, the animation will end immediately. With Movement Input allows the animation to blend out early if the character is moving, ideal for transitions back to walk/run cycles. If Falling ensures the animation completes naturally unless the character is in a falling state, providing a seamless finish when there's no movement input.

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