User guide & changelog

What AlphaPaint does

Find your way around

One place to paint and refine.

1. Paint controls
   Editing/Playback, Erase/Restore, duration, brush settings and pressure.
2. Alpha handling
   Preserve or edit incoming alpha; choose input and output association.
3. Stroke Stack
   Review, adjust, reorder and time your recorded strokes.

Start your first mask →

AlphaPaint creates editable visibility masks by painting directly in the After Effects Composition panel. Apply it to a layer, erase to reveal the layers underneath, and restore areas when you need them back. You can judge the result against the full composition while you work.

AlphaPaint keeps your source footage intact. Your strokes are saved with the effect in the After Effects project, and can be enabled, disabled, reordered and adjusted later. It paints a single-channel alpha mask, not RGB colour.

Installation and activation

AlphaPaint is a Windows 64-bit plugin. Check the system requirements supplied with your download before installing.

The easiest way to install and license AlphaPaint is by using the aescripts + aeplugins manager. To install a trial, select Add Trial from the Account menu.

If you prefer to install manually:

1. Close After Effects before installing or replacing the plug-in.
2. Copy AlphaPaint.aex into your After Effects Plug-ins folder, or follow the installation instructions supplied by your distributor. Keep only one installed copy.
3. Open After Effects. Find AlphaPaint under Effect > SpatialOps > AlphaPaint, or search for AlphaPaint in Effects & Presets.
4. Apply it to a layer. In Effect Controls, use Register to open the licensing window.
5. Paste your licence code and choose Activate. Use Help in that window for licensing assistance. Once registered, the same window provides Deactivate and Close.

Keep the plug-in installed on machines that need to render your projects. Licence requirements still apply when rendering.

Trial mode

The trial lasts 14 days from your first use. Reinstalling or updating AlphaPaint does not restart the trial.

The trial allows 25 stored strokes across the entire project, shared between all AlphaPaint effects and compositions. Each painted stroke counts once, regardless of its duration. Disabled strokes and invert layers also count. Deleting strokes, or clearing a mask, frees capacity. Disabling a stroke does not.

A Trial mode badge appears in previews and exported renders, with the number of days remaining (for example, 14 days left or 1 day left). Activating removes the notice and stroke limit from newly rendered output.

Projects containing more than 25 entries remain intact in trial mode. You can edit or delete existing entries, but cannot paint another stroke or add an invert layer while at or above the limit. When the trial expires, painting, stroke editing and effect output require activation. Your saved strokes are retained.

Your first mask

EditingEnable Composition-panel painting.

EraseRemove visibility to reveal layers below.

RestorePaint visibility back.

ConstantKeep new strokes active across the layer.

1. Select the layer you want to paint on. Put a background or another layer beneath it so you can see the revealed areas.
2. Apply AlphaPaint. Select the effect in Effect Controls, expand its AlphaPaint interface and keep the Composition panel visible.
3. Choose Editing Mode, shown by the pen-in-a-box icon. The play icon indicates Playback Mode.
4. Choose the red Erase minus button. Set Size and start with Hardness, Opacity and Flow at 100% for an obvious test stroke.
5. Choose Constant to keep the stroke visible throughout the layer, or Single to limit it to the current layer frame.
6. Left-drag with a mouse or paint with your tablet in the Composition panel. Erased areas reveal the layers below.
7. Select the green Restore plus button and paint back over an erased area.
8. Switch to Playback Mode when you want to inspect or play the result without editing it. Save your project normally to retain the strokes.

Keep the effect selected for Composition-panel painting. Middle and right mouse buttons are not paint buttons. AE still controls which navigation and context actions are available in the viewer.

Brush controls

SizeBrush diameter.

HardnessEdge falloff.

OpacityStrength of one stroke.

FlowBuildup along a stroke.

Drag a control's numeric value, icon or label horizontally to change it. Ctrl gives finer adjustment; Shift gives larger steps. Release to keep the value, or press Escape during a drag to cancel it.

• Size: Brush diameter, from 1 to 8192 layer pixels. The viewer outline shows the brush footprint through the layer's transform.
• Hardness: Edge softness. At 100%, the brush has a hard edge; lower values create a softer falloff.
• Opacity: Limits how strongly one stroke changes the mask. Separate strokes can build further.
• Flow: Controls how quickly the brush builds up as you move. Lower Flow lets you build transparency more gradually. Flow does not change the spacing of the brush marks, and holding the pen still does not keep adding paint.

The top controls set up new strokes. To change a recorded stroke, use its editable fields in the Stroke Stack. The brush icons change to help you recognise your current settings.

Erase and Restore

With the default Incoming Alpha: Preserve setting, the mask starts fully visible. Erase moves it toward black, Restore moves it toward white, and intermediate values give partial visibility. Your original transparency is preserved.

Restore in Preserve mode restores visibility removed by AlphaPaint. It does not create opacity outside the alpha supplied by the source and preceding effects. See Alpha handling for the alternative Editable mode.

Hold Alt to temporarily swap Erase and Restore. Pressing or releasing Alt while painting changes the whole active stroke and updates its result live. The toolbar's selected mode stays unchanged.

Viewport shortcuts

• [ / ]: Decrease or increase brush size.
• Ctrl + [ / ]: Make smaller size changes.
• Shift + [ / ]: Make larger size changes.
• Ctrl + left-drag: Resize in the viewer instead of painting. The outline stays centred at the initial click. Drag along the layer's horizontal direction to change size; this direction follows the layer's rotation. Release to keep the size; Escape cancels.
• Shift while painting: Constrain the line to the viewer's horizontal, vertical or nearest 45-degree direction. Pressing Shift during a stroke starts a constrained segment at the last painted point; releasing it resumes freehand painting.

If a shortcut does not respond, click in the Composition panel and make sure AlphaPaint is selected.

Tablet pressure

The stylus button enables pressure. Choose the affected brush setting beneath it; the small pressure badge follows your selection.

Click the stylus button to turn pressure on or off. Pressure is on by default. The dropdown beneath it selects Size, Hardness, Opacity or Flow for new strokes. It is disabled when pressure is off or Playback Mode is selected.

Pressure controls how much of your chosen setting is applied. For example, with Size selected, light pressure gives you a smaller brush and full pressure reaches the size you have set. The other brush settings stay as you set them. A small pressure badge identifies the affected brush control.

Pressure is saved with each stroke, so it looks the same when you reopen the project—even without the tablet connected. Mouse painting uses the full values shown in the brush controls.

This plugin requires a compatible Wintab tablet driver for pressure. Windows Ink-only pressure is not supported. If pressure is missing or inconsistent, check the tablet driver's Wintab support and application settings. Turn pressure off to compare the same brush at its full configured setting.

Stroke duration and frame timing

SinglePaint on one layer frame.

ConstantPaint throughout the layer.

The two duration buttons choose the lifetime of new strokes:

• Constant: Applies throughout the layer's duration.
• Single: Applies on the layer frame on which it was painted.

Different durations can coexist in one effect. A recorded stroke can also be changed to Range in the Stroke Stack, with editable Start and End frames.

Frame values use the layer's time, not necessarily the composition's displayed frame number. Layer offsets, stretching and time remapping can affect where those frames appear in the composition. Check the result at the intended composition time after retiming a layer.

Working with the Stroke Stack

The Stroke Stack sits below the alpha controls and lists operations in the order they are applied. Order matters: a restore after an erase can produce a different result from an erase after a restore.

While you paint, the composition updates but the stack keeps showing the completed strokes. The new row appears when the gesture ends. Stack editing is temporarily locked during an active paint gesture.

Select, reorder and delete

Move earlierMove selected entries up.

Move laterMove selected entries down.

Delete selectedRemove the selected entries.

Current frameFilter the displayed list.

• Click a stroke's number to select it. Numbers identify strokes and stay with them when reordered.
• Shift-click another stroke number to select a range. Selections are retained when moving between pages, allowing batch operations across pages.
• Use the up/down arrows in the left menu to move selected strokes earlier or later. The strokes within your selection stay in the same order.
• Hold the left mouse button on a stroke number and drag to reorder. An insertion marker shows the destination. Release to apply the move, or press Escape to cancel.
• Use the ordinary trash-can button to delete the selection.

The page buttons below the table move between pages. With the stack focused, Page Up/Page Down change pages and Home/End jump to the first or last page. The filter icon with a clock shows only entries active on the current frame; Constant entries remain visible because they are active on every frame. Filtering does not delete or disable anything.

Editable row fields

• On: A shaded box means enabled; an empty box means disabled. Click and drag up or down the On column to apply the first chosen state to other visible rows. Escape cancels the sweep.
• Mode: Click a paint stroke's mode to switch Erase/Restore. This also resets its Colour to black/white respectively.
• Colour: The single-channel mask target, from 0 (black/hidden) to 1 (white/visible). This is not an RGB paint colour. Drag the value or swatch to set a grey target.
• Opacity: Drag to change the strength of that stroke. The swatch illustrates transparency.
• Hardness: Drag to change that stroke's edge softness.
• Lifetime: Click to cycle Constant > Single > Range > Constant.
• Start / End: Drag horizontally, or click once and type a frame number. Enter or Tab confirms typed input; Escape cancels. Single exposes Start only. Range exposes both Start and End, including the end frame. Constant has no editable frame boundaries.

Hold Ctrl for smaller value changes or Shift for larger changes. You can move or delete several selected strokes together; changing a value affects the row you edit. You cannot move individual points along a painted stroke.

Invert and Clear

InvertAppend an inversion operation.

Clear AllRemove the full history after confirmation.

The diagonally divided square in the left menu adds an invert layer at the end of the operation stack. It reverses the accumulated mask at that point in the order. Its row is labelled layer, and its lifetime can be adjusted. Invert rows do not have paint-stroke Mode, Colour, Opacity or Hardness fields.

The red trash can with an exclamation mark, at the bottom of the menu, is Clear All. It asks for confirmation before removing the effect's entire history, on all frames. This is different from deleting the selected strokes.

Use After Effects' normal Undo/Redo commands for supported edits. Save your project before major changes or before replacing an installed plug-in version.

Alpha handling

All six alpha buttons sit in one row, arranged into three independent pairs. Both association settings default to Premultiplied; Incoming Alpha defaults to Preserve.

Incoming Alpha: Preserve or Editable

Preserve keeps the incoming alpha as the maximum visibility. For example, if the incoming alpha is 25%, a full Restore stroke returns it to 25%, not 100%. Use this for a conventional nondestructive layer-mask workflow.

Editable treats the incoming alpha as a starting value that strokes can change. In that same example, a full Restore stroke can raise 25% alpha toward 100%. Use it when you deliberately want to paint opacity back into alpha produced by an earlier effect.

Editable uses the RGB colour that actually reaches AlphaPaint. It cannot recover colour that an earlier effect has discarded. If an upstream effect removed both colour and alpha, restoring opacity can reveal black. Try moving AlphaPaint earlier in the effect order if you need access to colour before another effect removes it.

Input Alpha: Premultiplied or Straight

This tells AlphaPaint how the colour reaching it is stored. Premultiplied means RGB is already multiplied by alpha. Straight means RGB is unassociated with alpha. Match the colour format reaching AlphaPaint after any effects above it. If you are unsure, start with the default Premultiplied setting.

Output Alpha: Premultiplied or Straight

This chooses how AlphaPaint saves colour alongside transparency for the next effect. Premultiplied multiplies colour by the resulting alpha; Straight outputs unassociated colour. Leave the defaults unless your surrounding workflow requires something else. Incorrect input/output association can cause dark or bright edges.

Suggested workflows

Refine an existing cutout

Place AlphaPaint after the effects that create the cutout. Keep Incoming Alpha on Preserve. Use a soft Erase brush to remove unwanted edges, then Restore to correct areas you removed. Inspect the result over a contrasting background.

Make a local frame correction

Go to the affected frame, select Single, and paint the correction. Step to neighbouring frames to confirm its lifetime. If it needs to last longer, change the row to Range and enter Start and End.

Build a reusable holdout

Choose Constant and paint the holdout while viewing the composite. Use several modest strokes so corrections remain easy to isolate. Switch to Playback Mode when finished to lock the brush and stack without disabling the result.

Performance and troubleshooting

AlphaPaint supports 8-bit, 16-bit and 32-bit float projects, with GPU acceleration on compatible NVIDIA CUDA cards, CPU rendering and After Effects multi-frame rendering. The acceleration available depends on your project settings and hardware.

The whole composition affects how quickly you see your brush strokes. Heavy effects, large soft brushes and many strokes can slow previews. Try a lower Composition preview resolution, or temporarily turn off effects you do not need while painting. Turn them back on before checking your final result. AlphaPaint does not change your project bit depth automatically.

I cannot paint

Check that the correct layer and AlphaPaint effect are selected, Editing Mode is enabled, the Composition panel is receiving input, and your licence or trial permits editing. In trial mode, also check the project-wide stroke count. Expand AlphaPaint in Effect Controls if its controls are hidden.

Restore does not bring an area back

In Preserve mode, Restore cannot exceed incoming alpha. Check the alpha from the source and effects before AlphaPaint, and check whether the stroke is active at the current layer frame. Use Editable only when you intend to change incoming alpha itself. Remember that missing RGB cannot be recreated.

My strokes are missing on another frame

Check Lifetime, Start/End, the row's On state and layer-time mapping. The current-frame filter only changes the displayed list; turn it off to find entries active at other times.

The stack is locked

Switch from Playback to Editing and finish any active viewport gesture. An expired or invalid licence also disables editing.

There is a Trial mode notice after activation

Request a fresh frame render. If AE is still displaying an old cached frame, refresh or purge the affected preview cache and render again. A previously exported file does not change when you activate.

Scope and compatibility

This plugin is for Windows. A macOS version is not included. Wintab pressure support is separate from Windows Ink. AlphaPaint paints transparency on a layer. It does not clone RGB colour or turn an existing alpha channel into brush strokes.

If your layer uses 3D transforms, Collapse Transformations, Continuous Rasterisation or time remapping, check the mask carefully before your final render. Keep a backup before changing plugin versions, as older versions may not open strokes saved by newer versions.

Changelog

1.0 — Initial release

AlphaPaint brings nondestructive alpha-mask painting directly to the After Effects Composition panel, so you can erase and restore a layer while viewing the full composite.

Painting

ErasePaint transparency.

RestoreRecover visibility.

PressureFour selectable targets.

• Erase and Restore brushes with adjustable Size, Hardness, Opacity and Flow. Hold Alt to switch the whole active stroke live.
• Live brush outline, smooth strokes and pressure-sensitive painting with a compatible Windows Wintab tablet driver.
• Selectable pressure target: Size, Hardness, Opacity or Flow, with a badge identifying the affected control.
• Bracket-key brush sizing, Ctrl-drag viewport sizing, fine/coarse value adjustment and Shift-constrained horizontal, vertical and 45-degree lines.
• Constant and Single-frame painting, with editable Range lifetimes for recorded strokes.
• Editing and Playback modes to enable interaction or lock the brush and stroke stack while retaining the rendered mask.

Editable stroke workflow

• Editable strokes saved in your After Effects project, without altering the source footage.
• Paged Stroke Stack with cross-page Shift selection, group movement/deletion and drag reordering.
• Per-stroke enable/disable, Erase/Restore mode, mask Colour, Opacity, Hardness and lifetime editing.
• Draggable Start/End frame values with click-to-type entry.
• Current-frame filtering, visibility sweeps, invert layers and confirmed Clear All.
• Undo and redo using the familiar After Effects commands.

Alpha and rendering

• Preserve or Editable incoming alpha, with separate Premultiplied/Straight input and output controls.
• Support for 8-bit, 16-bit and 32-bit float projects.
• GPU-accelerated on eligible NVIDIA CUDA cards, with CPU and multi-frame rendering support.

Licensing

• A 14-day trial with a 25-stroke limit across the whole project and a styled Trial mode badge showing days remaining in previews and exports. Activation removes the trial restrictions; saved strokes are retained.

Platform notes

• Windows 64-bit .aex release, under SpatialOps in the After Effects Effect menu.
• Tablet pressure requires a compatible Wintab driver; Windows Ink-only pressure is not supported.
• RGB painting and individual stroke-point editing are not included.