Auto Domain Node

Auto Domain scans the image on every frame and identifies the smallest rectangle enclosing the non-zero / non-transparent pixels (based on the Threshold). That rectangle becomes the DoD = downstream nodes only compute that area.

Especially useful for animated elements: a subject moving through a large canvas → the DoD follows automatically. It saves you from animating a SetDomain by hand.

• Effects Library: Tools > Misc > Auto Domain
• Quick add: right-click in the Node Editor → Add Tool > Misc > Auto Domain

SetDomain

DoD set manually through Top/Bottom/Left/Right. Animatable but explicit.

Auto Domain

DoD calculated automatically from the non-zero content. No need to know where the useful pixels are.

Rule: known / fixed area → SetDomain. Unknown / animated area → Auto Domain.

• Input (orange) - the image to analyze.
• Effect Mask (blue) - optional.

Animated subject in a large canvas:
Animated element (4K canvas, moving 500x500 subject)
   → Auto Domain (Threshold = 0.01, Padding = 10)
   → Glow / Blur / etc.
   → Merge with BG
= processing only on the subject area, which follows its
movement automatically

Particles in the frame:
Particles → Auto Domain (large Padding for downstream blur)
         → Bloom / Glow
         → MediaOut

Cleanup + Auto Domain combination:
MediaIn → Color Cleanup → Auto Domain
       → Heavy effects downstream = optimized on the useful area

Multiple elements:
Two elements merged → Auto Domain
                   → processing
                   = area enclosing both

Threshold (default: 0.01)

Threshold above which a pixel counts as useful content. Low = strict (almost every non-zero pixel is included), high = ignore faint pixels.

Channel (default: Alpha)

The analyzed channel. Alpha for images with transparency, Luminance for full-frame images, RGB max as needed.

Padding (default: 0)

Margin added to the calculated DoD. Critical if downstream effects (blur, glow) spill beyond the strict content. 10-50 pixels recommended.

Min Size (default: 0)

Minimum DoD size. Avoids areas that are too small and would cause artifacts.

• Moving element in a large canvas - a logo moving across a 4K canvas: Auto Domain shrinks the area to compute by following the logo.
• Fluctuating particles - particles whose emission area varies: Auto Domain adapts automatically.
• Roto / matte with variable content - the matte of a subject that may appear / disappear from the frame from one frame to the next.
• Optimizing generic comps - when you do not know exactly where the content will be, Auto Domain gives you the optimization with no setup.
• Pipeline templates - Fusion templates that must work with different content: Auto Domain = automatic adaptation.

• Padding is a must with blur/glow - otherwise the effects get cut off at the edge of the strict DoD. 10-50 px depending on the strength of the effect.
• Threshold is sensitive to noise - on noisy images, raise the Threshold to ignore the background noise (otherwise DoD = full canvas).
• Channel = Alpha for transparent images, Luminance for a beauty plate.
• The cost of the analysis - Auto Domain has to scan the image on every frame. On very high-resolution images, the optimization gain can be canceled out by the cost of the analysis. Test case by case.
• Cache upstream if possible - if the source image is heavy to compute, cache it before Auto Domain so the analysis is fast.
• Prefer SetDomain if the area is known - Auto Domain has a cost. If the area is fixed and known, a manual SetDomain is more efficient.
• For workflows with several separate elements, consider one Auto Domain per element before the Merge, for separate optimizations.