8. Filters¶
Everything below is a sublayer like any other: it has a row, a mute, an opacity and a place in the stack. They all come from the OP Filters shelf — the Filters button on the add row opens it as a popover — where every entry is a node group named filter_…, so your own appear beside them (chapter 19). Anchor, ID Map, Choke and the pixel filters are built into Overpaint; their shelf entries are only the handles you drop.
Anchor — mask bus or image bus¶
An Anchor reuses another sublayer's stack result instead of duplicating it. Author a mask once, then anchor it from other layers. Anchors work across layers and across channels: you can aim a mask painted for Colour at Roughness, or drive a wear effect on one channel from the content of another. Anchors on the image bus take part in the layer's accumulated content like any other palette. When the anchor's target cannot be evaluated the layer says so instead of guessing; take a look inside node inspenctor.
ID Map — mask bus¶
A mask picked from colours. Add ID Map from the Special Sublayers menu, then load an ID map image or generate one from the mesh (by connected element, by UV island, or per face). Use the eyedropper to click directly on the model and add the colour under the cursor to the mask. Each picked colour gets a name and the list has a tolerance slider.
Choke — mask bus, or image bus¶
Erodes or expands the edge of a mask by a distance. Put a Choke above a Paint or Procedural mask to tighten or grow it. On layers that carry image content the Choke can also sit on the image bus, where it erodes the accumulated content's coverage the way it erodes a mask. The Choke box in the inspector has a Bus switch with two buttons, Mask and Image.
Blur — mask bus, or image bus¶
Softens everything accumulated below it. Its radius lives on a value node rather than a plain property, which is what lets the viewport preview it live while you paint. Large radiuses use a pyramid downscale so they stay fast. Scale (%), plus the set-wide Blur Quality slider in the main panel.
Slope Blur — mask bus, or image bus¶
A variable-radius blur: the amount of smearing follows the values underneath, so a mask streaks the way weathering runs rather than fogging evenly. Radius, Mode (Smear, Erode, Dilate), Samples, Strength, Slope Softness, Invert, and the Slope Source — the filter's own luma or alpha, the sibling's luma, alpha or channel, or an image texture.
Directional Blur — mask bus, or image bus¶
Blurs along one direction only — motion, brushed metal, rain streaks. Radius, angle.
Sharpen — mask bus, or image bus¶
Unsharp-mask sharpening: re-crisps an edge that a blur or a bake softened. Radius, strength.
High Pass — mask bus, or image bus¶
Keeps the fine detail and throws away the broad tones. Useful for lifting surface texture out of a photo before you blend it. Radius.
Curves — mask bus, or image bus¶
A curve widget over what is below — the general-purpose tone control. It adapts to what it sits on: an RGB curve on colour, a float curve on a mask.
HSV — mask bus, or image bus¶
Hue, saturation and value, with a factor to dial the whole thing back. Hue, saturation, value, factor.
Brightness/Contrast — mask bus, or image bus¶
Exactly what it says, on whichever bus it sits. Brightness, contrast.
Gamma — mask bus, or image bus¶
A gamma curve — the quickest way to lift or crush a mask's midtones. Gamma.
Ramp — mask bus, or image bus¶
Pushes the result through a colour ramp, so a grey mask becomes whatever the ramp's stops say. The fast way to turn a generator into bands, to tint a mask, or to harden a soft gradient into a step.
Remap — mask bus, or image bus¶
Maps an input range onto an output range: pull the ends in to squeeze a soft mask into a hard one, or push them out to soften a hard one.
Drop Shadow — mask bus, or image bus¶
Offsets a copy of what is below, blurs it and lays it underneath — decals and stencils stop looking flat. Offset X, offset Y, radius, colour, opacity.
Glow — mask bus, or image bus¶
A bloom out of the bright parts of what is below. Threshold, radius, intensity.
Mask Outline — mask bus, or image bus¶
An outline traced from the mask's edge. Width, softness.
Posterize — mask bus, or image bus¶
Quantises to a fixed number of steps — banding on purpose, and a quick way to turn a smooth generator into hard zones. Levels.
Blur and Slope Blur show a quick preview while you paint, then update to full quality when you stop. The other pixel filters show their committed result. Curves, HSV, Brightness/Contrast, Gamma, Ramp and Remap work live.