MultiMerge

Use MultiMerge when several simple 2D elements form one logical block: title, subtitle, logo, HUD, cards, icons or decorative passes. It replaces a long chain of basic Merge nodes with one managed layer stack while retaining independent controls for each foreground.

The node has one Background and a dynamic set of Foreground inputs. Background is the orange base input. Current Resolve documentation describes MultiMerge foreground inputs as white; connecting a new source creates the next consecutive Foreground socket and a matching row in the Layer List. The three Foreground ports shown in this page's practice signatures are therefore representative, not a hard node limit.

Background also determines the Output resolution. Foreground images may use other dimensions, but the final canvas follows the image connected to Background. Verify the Background first before diagnosing apparent scaling or framing problems elsewhere in the stack.

Read the Layer List as a stack: rows nearer the top are closer to the foreground while lower rows sit nearer the background. Drag rows to reorder them. Selecting a row does not reorder it; it only makes that layer active for the controls below and highlights the corresponding pipe in the Flow.

Each row has an enable checkbox. Disabling a layer removes its contribution without deleting its slot or source relationship, and layer order plus enable/disable state can be keyframed. That is useful for simple switching, although explicit Merge/Switch branches are still clearer for complex logic.

Disconnecting a Foreground cable does not automatically remove the Layer List row. The slot remains and is shown struck through so a source can be auditioned, replaced or reconnected without losing stack order. In current Resolve 21 the context menu also includes Delete Layer: it removes the layer slot and disconnects its pipe but does not delete the upstream source tool from the Flow.

For large stacks, Split Here is a first-class maintenance operation. It creates a second connected MultiMerge: the selected layer and every layer above it move into the new node, while the original MultiMerge feeds the Background of that new node. This is safer than manually rebuilding an overloaded stack.

Layer naming is part of the workflow. In current Resolve 21 the default layer name is based on the connected source; a layer can still be renamed manually or renamed to match its source. Name upstream tools clearly—TITLE, SUBTITLE, LOGO, BADGE, GLOW—before the stack becomes large so the Layer List doubles as readable documentation.

Resolve 21 also supports multi-select in Layer List: Shift selects a range while Command selects non-adjacent layers. This is selection workflow, not a separate authored parameter. Go To Source in the layer context menu selects the connected source tool and opens its Inspector, which is especially useful when a large MultiMerge hides the origin of the active row.

Selecting a layer exposes that layer's Merge controls. Center, Size and Angle affect only the active Foreground. Apply Mode, Operator, Subtractive/Additive, Alpha Gain, Burn In and Blend control how that layer composites with the stack already below it. These are per-layer controls, not global MultiMerge settings.

Apply Mode and Operator are separate concepts. Apply Mode chooses the color blend behavior. Operator chooses the compositing operation and is conditional; the Merge controls expose it only in supported Apply Modes, including Normal and Screen. Dropdown choices are not separate authored controls.

Subtractive/Additive, Alpha Gain and Burn In are alpha/compositing controls that can expose premultiplication problems on translucent edges. They do not justify inventing separate MultiMerge-specific Pre-Multiply/Post-Multiply toggles. If edges fringe, inspect the source alpha/premultiplication and the actual Merge controls first.

Filter Method governs resampling for the selected layer's built-in transform. Window Method is conditional for filters that use a window, while Edges chooses boundary sampling such as Canvas, Wrap, Duplicate or Mirror. These controls become most visible after scale, rotation or translation exposes source boundaries.

Invert Transform and Flatten Transform are technical per-layer transform controls. They are not substitutes for a fictional Pivot or Flip/Flop inventory; those separate controls are not included in the evidence-backed MultiMerge control set on this page.

Reference Size changes how Center coordinates are presented. Use Frame Format Settings follows the frame format; Reference Width and Height allow a manual reference. This does not change the MultiMerge canvas or Output resolution, which still comes from Background.

MultiMerge also has the normal Settings tab shared by many Fusion tools. Node-level Settings > Blend affects the overall MultiMerge result. Do not confuse it with the per-layer Blend in the selected layer's Merge controls. Generic Settings controls are not inflated into the MultiMerge-specific authored inventory here.

The blue Effect Mask is a global contribution mask for MultiMerge. White allows the assembled foreground stack to affect the Background; black leaves the Background alone. It is not a per-layer mask. If TITLE or LOGO needs its own matte, constrain that upstream branch before MultiMerge or use a more explicit compositing branch.

MultiMerge works best when many simple layers belong together. If every layer has a long independent processing pipeline, separate Merge branches remain easier to debug, bypass and reuse. A compact graph is valuable only while it keeps the logic visible.