How to Add Width Controls to Rubber-Hose Limbs for Foreshortening in After Effects

First identify the properties that change the centerline and those that change the silhouette. In Rubberhose 3, Hose length determines the controller distance at which the hose becomes straight. Direction controls how the hose bends, and Battle Axe specifically suggests animating Direction to suggest movement toward or away from the camera. These are useful pose controls, but they do not replace control over the visible width. Battle Axe: Controls

Battle Axe documents hoses as shape layers whose appearance can combine strokes, fills, layer styles, and effects. It also distinguishes style presets from bend presets: bend presets do not change thickness. For this setup, begin with a simple hose rendered by one stroke so that the width controls have an obvious target. Battle Axe: Styles

Use three independently adjustable values: a maximum stroke width, a start-width percentage, and an end-width percentage. Keeping them separate lets you change overall thickness without rebuilding the taper. It also lets you reverse the apparent depth direction without reversing the limb’s path.

Save a working copy of the project before changing the rig. Choose one limb and a neutral pose where its full contour is easy to see. Temporarily work with a plain style if decorative details make the silhouette difficult to judge.

Expand the hose layer’s Contents and locate the stroke that actually renders the limb. To identify it, make a small temporary width adjustment, confirm the visible result, and undo. If several strokes contribute to the appearance, decide which represents the main body before proceeding.

Do not assume that the path’s start is the shoulder or hip. Test it: change one endpoint’s taper width and observe which end responds. Record the mapping in the controller names—for example, “Start Width — Shoulder” and “End Width — Wrist.” This small check prevents reversed adjustments later.

For a new native shape-layer test, draw an open curved path with a stroke and no fill. For an existing hose, retain its generated path and rig connections. The aim is to change the rendering properties around that path, leaving its pose system usable.

Under the visible stroke, expand Taper. After Effects provides Start Length and End Length to define the affected portions, plus Start Width and End Width to shape their thickness. An endpoint width has no visible taper effect when its corresponding taper length is zero. Percentage length units make the transition relative to the path length. Adobe: How to taper shape strokes

Use this initial configuration:

• Set Length Units to Percentage.
• Set Start Length and End Length to 50% each.
• Set Start Width and End Width to 100%.
• Set Start Ease and End Ease to zero for an uncomplicated initial transition.

This is a proposed starting profile, rather than a required rig specification. The neutral endpoint values give you a baseline before introducing a taper. Once the controls work, adjust the transition lengths and easing to suit the character’s contour. Keep those settings fixed during the first pose test so you can judge width changes independently.

Create a null layer named “Limb Width Controls.” Apply three Slider Control effects through Effect > Expression Controls > Slider Control. Rename the effects and enter the following initial values. Adobe supports placing expression controls on a null and referencing them from properties on other layers. Adobe: Using expression controls

Slider name	Initial value	Target property
Maximum Width	32	Stroke Width
Start Width Percent	100	Taper > Start Width
End Width Percent	100	Taper > End Width

For each target property, Alt-click its stopwatch on Windows or Option-click on macOS to enable an expression. Drag the expression pick whip to the matching slider’s numeric value. Repeat for all three properties, checking each connection before continuing.

Use the pick whip so After Effects creates the references using your actual layer and effect names. Rename controls before connecting them, and use distinct names for each limb if you build several control layers. Adobe recommends descriptive effect names and explains that linked expression controls can be keyframed. Adobe: Using expression controls

Test each slider separately. Maximum Width should change the main stroke thickness. Start Width Percent should affect the confirmed start end; End Width Percent should affect the other end. Return both endpoint sliders to 100 before starting animation. This procedure uses interface connections and does not require a custom script.

Build three held poses before polishing any transitions. The following values are illustrative design inputs, not measured perspective results. They assume that the path starts at the shoulder and ends at the wrist, with the taper lengths configured above.

Test pose	Maximum Width	Start Width Percent	End Width Percent	Drawing intention
Sideways neutral	32	100	100	Establish the normal silhouette
Wrist approaching viewer	44	65	100	Emphasize the wrist end
Wrist receding	32	100	65	Emphasize the shoulder end

For the approaching pose, bring the wrist closer to the shoulder in the composition to reduce the limb’s visible reach. Adjust the bend until the shortened silhouette is deliberate, then introduce the width difference. Judge the result with the hand visible, because its size and overlap help communicate the intended orientation.

For the receding pose, reverse the width emphasis and reconsider where the hand sits relative to the character. Simply exchanging two width values may leave an ambiguous pose. Check the entire contour, including where the limb emerges from the torso and where it meets the hand.

As an animation design choice, avoid automatically driving width from the distance between the two controllers. A short endpoint distance can describe several poses, including a sideways bend. Independent width controls preserve your ability to choose the intended depth reading.

If a pose only reads after an extreme width change, revisit the centerline and overlap first. Use thickness to reinforce an understandable drawing. Continue adjusting the three held poses until each is readable at the intended viewing size.

Once the held poses work, keyframe the three sliders at the corresponding pose times. Preview a slow transition first. Inspect the frames between poses as carefully as the endpoints: a convincing pair of drawings can still produce an awkward intermediate silhouette.

A useful diagnostic order is position, bend, width profile, then timing. If the limb appears to swell before it turns, shift or soften the width change. If the near end becomes broad while the visible reach remains unchanged, check whether the motion needs a clearer shortening phase.

Check the hand or foot attachment throughout the transition. A wider wrist with a small, unchanged hand may produce an unintended collar shape. Adjust the adjoining artwork where the drawing requires it, or reduce the local width change. Work from the combined silhouette rather than evaluating the hose alone.

Do not apply the same width animation to every limb by default. Finish one representative motion, then use it as a setup reference. Each limb still needs its own pose and contour decisions.

Symptom	Check	Practical next step
Endpoint slider appears inactive	Corresponding taper length and selected stroke	Use a nonzero length and verify the visible stroke
Wrong end changes	Actual path direction	Correct the controller labels or connections
Width reference reports an error	Layer and effect names	Reconnect with the pick whip
Limb looks inflated through the middle	Maximum width and taper transition	Reduce the maximum or reshape the transition
Shortened pose remains ambiguous	Centerline, endpoint artwork, and overlap	Redraw the pose before increasing the taper
Width controls stop behaving after styling changes	Stroke receiving the expressions	Inspect and reconnect the intended rendering properties

After the motion works, preserve the style for reuse. Battle Axe supports saving and copying hose styles, but test the resulting setup on another hose before relying on it: confirm that its width references address that limb’s intended controls. Battle Axe: Styles

A useful finished rig lets you return immediately to a neutral thickness, emphasize either endpoint, and revise the pose without rebuilding the width setup. Keep the three controls simple, test them in both depth directions, and refine the silhouette at the scale where the character will actually be seen.

• Battle Axe, Controls.
• Battle Axe, Styles.
• Adobe, How to taper shape strokes.
• Adobe, Using expression controls.