Display Masks

Display masks hide regions of a display's output by applying an alpha overlay. They are used to cut spilled projector light at scenic edges, shape output for non-rectangular surfaces, and define custom blend regions between projectors.

Masks live in the display's screen space, independent of warp geometry. The renderer samples the mask alongside the source content, so the mask stays locked to what it covers as the warp transforms the output onto the physical surface. Warp repositions pixels; masks decide which pixels are visible.

Opening the Mask Editor

Device Properties → Mask → Custom Mask has the toggle and entry point:

• Enabled — turns the custom mask on or off for the display.
• Edit — opens the mask editor in its own window.

The editor can also be opened by right-clicking the display in the Devices window and choosing Edit Display Mask.

The Mask Editor

The mask editor is a separate window with two modes, switched from the toolbar:

• Edit Surfaces — manage the surfaces that make up the mask. Add, remove, rename, enable, or disable each surface, and select one to edit its points.
• Edit Points — edit the junction points and Bézier curves of the selected surface.

A panel on the right lists every surface on the display with a per-surface enabled checkbox. Disabled surfaces are kept but excluded from the output.

Mask Surfaces

A display can hold any number of mask surfaces, composited together. Each surface has:

• Surface Name — text label to identify the surface (e.g. "Left Spill Cut", "Scenic Border").
• Gamma Correction — slider from 0.25 to 1.5 that shapes the brightness curve of the feathered edge. Default is 0.4545 (perceptually linear, 1 / 2.2).
• Enabled — from the surface list panel; turns this surface on or off without removing it.

Built-in Surface Types

From the mask editor toolbar, Add Geometry adds a surface pre-shaped for a common case:

• Add Left Mask / Add Right Mask / Add Top Mask / Add Bottom Mask — cover one edge of the display with a feathered transition toward the centre. Useful for blending the overlap region with a neighbouring projector.
• Add Rectangle Mask — a rectangular cutout with feathered edges on all four sides. Useful for framing output within a scenic opening.
• Add Round Mask — an elliptical mask centred on the display, built from a grid of junction points with Bézier handles that approximate a smooth curve. Useful for circular screens or gobo-style outputs.

After creation, all points can be repositioned and the feathered edges adjusted.

Editing Mask Points

When a junction is selected, Device Properties → Mask Point exposes:

• Alpha Value — slider from 0 to 1. 0 is fully transparent (content visible); 1 is fully opaque (content hidden). The renderer interpolates alpha smoothly across the mesh between points.
• Make Black / Make Transparent — quick buttons that set the alpha value to 1 or 0.
• X Position / Y Position — the junction's location on the display, in pixels.
• Direction selector (Right / Up / Left / Down) — picks which Bézier handle of the junction you are editing.
• Length / Angle — distance (pixels) and direction (degrees) of the selected Bézier handle.
• Smooth junction — keeps the curve through the junction kink-free when both handles are moved. Corner junctions don't expose this toggle.

Ctrl + Click on a mesh curve inserts a new junction at that position, splitting the adjacent Bézier segments while preserving the overall shape. Press Delete to remove selected junctions.

Image Mask

A display can also use a single image asset as a mask layer — useful when you have a pre-rendered alpha map (for example exported from a 3D modelling tool or generated from a camera calibration).

Drag an image asset from the Asset Manager onto the mask editor to assign it. The image appears as a surface in the surface list with its own enabled checkbox. To remove it, right-click the editor and choose Remove Mask Image.

Gamma Correction

The gamma curve controls how the feathered edge of a surface falls from opaque to transparent.

• Lower values produce a softer, more gradual fade.
• Higher values produce a faster rolloff, concentrating the transition in a narrower band.

Gamma is critical when masks define the blend zone between two overlapping projectors. Mismatched gamma between the two displays produces visible intensity bands or dark seams in the overlap.

Typical Uses

• Cutting projector spill — use a side mask preset, then drag junction points to follow the edge of the scenic surface.
• Shaping output for irregular screens — combine junctions with Bézier handles to trace the contour of curved walls, set pieces, or architectural features.
• Custom blend regions — when automatic edge blending doesn't fit the geometry, define the blend manually with a mask, placing junctions along the overlap boundary and grading the alpha values.
• Multi-surface masks — combine several surfaces on one display (for example a side-edge blend and an irregular scenic cutout).

See Edge Blending for the automatic soft-edge feature, and Warp Geometry for surface-shape correction.