Cryptomatte
Decodes Cryptomatte ID matte data baked into a render engine’s EXR into a pickable object matte, selected by clicking directly in the preview.
Cryptomatte turns per-pixel object, material, or asset ID data from a 3D render into a matte you build by picking, with no re-rendering required. Point the node at a Cryptomatte-enabled EXR (its layers may carry an embedded manifest, or a sidecar JSON file next to it, either way the node finds it automatically) and choose which Crypto Type to decode when the file provides more than one, such as one layer per object and another per material. Multipart production renders work too, including files whose Cryptomatte layers span several EXR parts.
The primary workflow is picking directly in the preview: arm Pick+ or Pick- from the panel, or hold Ctrl and click (Ctrl+Alt+Click to remove) to add or remove whatever object is under the cursor, with a hover tooltip naming it first. To grab a whole region at once, sweep a rectangle with Ctrl+Shift held and every object it touches joins the selection in a single step (Ctrl+Alt+Shift+drag removes them). While a pick is armed the preview switches to Colored IDs so you can see exactly what you are clicking. Picking always samples the underlying ID data at full precision, never the on-screen display, so zoom level and color management never affect the result. The Matte List shows every selection as a removable entry, with an add-by-name field offering autocomplete from the file’s manifest.
Four output modes drive what the Image output shows: Matte (the accumulated grayscale selection), Colored IDs (the default: a stable random color per object, with picked objects highlighted yellow and the rest dimmed), Highlight (the beauty image’s brightness with the selection highlighted the same way), and Premultiplied (the beauty image cut out by the selection). Highlight draws its beauty from a wired Beauty input, or picks up the beauty layer inside the same EXR when nothing is wired, so it works standalone on a production render. Premultiplied needs a wired Beauty input for a correct, color-managed cutout, so that option stays unavailable until one is connected. Invert flips the Matte and Premultiplied results and the Matte output pin; it never touches the yellow selection highlights, so picking stays legible either way. The Matte output pin always carries the accumulated selection, regardless of the chosen mode.
Parameters
Section titled “Parameters”Pins
File
Path to the source EXR carrying Cryptomatte layers (cryptomatte/<key>/name + rank-layer header attributes)
Auto-reload when the file changes on disk (polls once per second)
Cryptomatte
Which declared Cryptomatte layer to decode (CryptoObject / CryptoMaterial / CryptoAsset / ...). Empty = the first layer found in the file
Selection
JSON array of selected object names (from the manifest) and/or raw "<hexid>" entries, e.g. ["bench","character"]. Edit by hand here, or via the picking UI on the Parameters panel / preview canvas
Output
What the Image output emits, independent of the Matte pin (always the selection coverage, Invert-applied):
- Matte: the accumulated selection as a grayscale matte.
- Colored IDs: a stable pseudo-random color per object (the default, useful for picking); selected objects highlight yellow and unselected objects dim.
- Highlight: the beauty image's brightness (a connected Beauty input, OVERRIDING the file's own beauty layer when one carries it, else the file's own beauty); selected objects highlight yellow and unselected areas dim.
- Premultiplied: the connected Beauty input multiplied by the selection matte (wire one for a color-managed result); with nothing wired, falls back to the matte itself.
Invert the matte (Matte and Premultiplied outputs and the Matte pin). Selection highlights are never inverted
Usage Tips
Section titled “Usage Tips”- Arm Pick+ from the panel, then click objects in the preview one at a time to build the selection; Escape or a right-click cancels an armed pick.
- With the node selected, Ctrl+Click adds and Ctrl+Alt+Click removes the object under the cursor without arming anything first.
- Ctrl+Shift+drag sweeps a rectangle and adds every object it touches in one step; Ctrl+Alt+Shift+drag removes them. Escape or a right-click cancels the sweep, and however many objects it picks up, undoing it is a single step.
- Colored IDs is the default and shows every distinct object in the file, so you can see what is there before you start picking.
- Highlight can read the beauty layer from the same EXR on its own; Premultiplied always needs a wired Beauty input so the cutout is color managed.
- Drag an EXR from your file explorer straight onto the Cryptomatte File field to load it without going through the file picker.
- No manifest in the file? Picking still works; unresolved objects show as raw hex ID entries instead of names.