Polygon Mask Node

The Polygon Mask is the roto node par excellence. You draw points around an object, and the tool generates a closed mask with adjustable Bézier curves. On every frame where you change the points, a keyframe is created automatically - the animation between keyframes is interpolated.

Used to isolate moving objects (face, arm, vehicle), create localized mattes for grading, or generate custom non-geometric shapes.

• Effects Library: Tools > Mask > Polygon
• Quick add: right-click in the Node Editor → Add Tool > Mask > Polygon
• Added automatically when you connect a mask to the Effect Mask input of another node.

Polygon Mask

Bézier curves with adjustable tangents. More precise for sharp corners and complex details. Needs more points for smooth curves.

B-Spline Mask

B-Spline curves (natural smoothing between points). Fewer points to get smooth organic shapes. Ideal for curved silhouettes (faces, arms).

Rule of thumb: angular / precise shapes → Polygon. Curved organic shapes (face, body) → B-Spline.

• Effect Mask (blue) - optional. An extra mask to combine (another Polygon, BSpline, bitmap mask, etc.) through the Paint Mode.

No main image input - the Polygon Mask only generates a mask to connect to the Effect Mask of another node.

Localized grading on a face:
MediaIn → Color Corrector ← Polygon Mask (face roto) as Effect Mask
       → MediaOut

Mask combined with others:
Polygon Mask (face) → BSpline Mask (hair, Paint Mode = Add)
                    → Effect Mask of a Blur

Roto with Soft Edge:
Polygon Mask (Level 1, Soft Edge 0.01, Filter Gaussian)
  → natural soft edges

Center X / Y

Overall position of the mask. Lets you move the whole mask without moving the points one by one.

Size

Overall scale of the mask. Can be animated for a mask that grows/shrinks.

Level

Mask opacity (0-1). 1 = fully opaque, 0.5 = semi-transparent (useful to dial the effect in).

Soft Edge

Feathers the mask edges. Selectable filter:

• Box: fast, simple.
• Bartlett: linear.
• Multi-box: fast Gaussian approximation.
• Gaussian: natural feather, recommended for quality.

Solid

On: filled mask (white/opaque inside). Off: outline only - transparent inside.

Border Width

Outline thickness when Solid is off.

Invert

Inverts the mask (masked areas become unmasked and vice versa).

Fill Method

How overlaps are handled in a complex mask:

• Alternate: alternating fill (even/odd rule).
• Non Zero Winding: fill based on the winding direction of the paths.

Paint Mode

How it combines with an incoming mask: Merge, Add, Subtract, Multiply, Invert, Replace, etc.

Click (Bézier)

Click to place a point. Drag to create Bézier tangents (smooth curves). The classic method.

Draw (freehand)

Continuous drawing with the mouse. Fusion generates the points automatically. Good for quick strokes to refine afterward.

Insert

Adds a point between two existing points of a mask you have already created.

Modify

The default mode for adjusting existing points and tangents.

Done

Closes the mask and locks the shape. Switch to this mode once you have drawn the points.

Roto Assist

Automatically snaps points to edges detected by contrast. Speeds up roto considerably on well-contrasted subjects.

• Rotoscoping a subject - trace around a person, object or vehicle to isolate it. Animate the points frame by frame or through automatic interpolation.
• Localized grading - a Polygon Mask on the face → Effect Mask of a Color Corrector = grading on the skin only.
• Localized cleanup / paint - a Polygon to isolate an area you want to retouch (dust, object removal) without affecting the rest.
• Garbage matte for a key - around a green screen, a Polygon to remove areas outside the subject (boom, equipment).
• Localized effect (blur, glow) - Polygon Mask → Blur Effect Mask = blur only inside the masked area.
• Combined mask through Paint Mode - several Polygon Masks in a chain, with Add/Subtract to build a complex shape (head + body + arms with Add, remove the background with Subtract).
• Custom shape for motion graphics - an animated polygon for logos, custom icons, graphic reveals.

• Draw mode for speed - draw freehand, then clean up in Modify. Much faster than placing every point individually for a silhouette.
• Turn on Roto Assist whenever you can - if the subject is well contrasted, Roto Assist snaps the points to the edges. A significant time saver.
• Gaussian Soft Edge for quality - the most natural feather. Box/Bartlett are for quick previews.
• Draw on a key frame - start on a frame where the subject is well posed and visible. Then scrub the timeline and adjust on the important frames - Fusion interpolates in between.
• Fewer points = better - 10 well-placed points > 50 needlessly dense points. The animation is easier to manage with fewer points.
• Attached Planar Tracker - for a subject moving on a flat surface, attach the Polygon Mask to a Planar Tracker through a modifier for automatic animation.
• B-Spline for organic curves - if you are rotoscoping a face, B-Spline often gives better results with fewer points.
• Fill Method Alternate by default - Non Zero Winding is useful for masks with nested areas (e.g. a donut = an outer circle + a hollow inner circle).