Paper

Paper is what the ink is multiplied over. An Ink Page Document (UInkPageDocument) gets it one of four ways, chosen by Paper at the top of the Paper & Ink section in the Page Editor’s left column: PaperMode defaults to Texture. The Paper dropdown is shown while you edit the front of a sheet; flip to the back and a Back paper dropdown takes its place — see the back’s paper.

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Texture asset

The simplest mode: point Paper texture (all pages) at any UTexture2D and every page in the document sits on it. With the picker left empty the page rides the project’s Default Paper Texture (Project Settings > Plugins > Inkwell, T_PaperPlain out of the box) — and only if that is also unset or unloadable does the page material fall back to its plain-paper color.

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Generated paper

Everything in FInkProceduralPaper, with the real defaults from InkPageLayer.h. Distances are in page pixels — pixels of the document’s Page Size Pixels — so they scale with the page rather than with the screen.

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Printing on real stock

Texture base turns the generated sheet from flat color into printed paper: the sheet starts as the base texture (or the project’s Default Paper Texture when none is named), Paper color multiplies over it as a tint — keep it near white to show the stock as authored — and the ruling, margin rule, holes and grain print on top exactly as they do on flat stock. It is the way to get “my parchment, but lined” without authoring a lined parchment texture. The generated result is cached like any other sheet, keyed on the resolved stock, so changing the project default regenerates every sheet that rides it.

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The four rulings

• Plain — no ruling at all. Still gets grain, a margin rule, and holes if you ask for them.
• Lined — horizontal writing lines every LineSpacingPx, starting TopMarginPx from the top and stopping the same distance from the bottom.
• Grid — the same rows plus vertical rules at the same pitch, so cells come out square. The column run is centered across the width, which leaves equal margins on both sides instead of a ragged part-cell jammed against one edge.
• Dotted — a dot at each grid intersection, radius 0.75 × LineThicknessPx. Dots sit on exactly the line centers Grid would use, so switching a sheet between Grid and Dotted never shifts the writing guides.

Rows, columns, and dots are unioned rather than summed, so a grid intersection does not print twice as dark as the lines crossing it.

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The margin rule

bMarginRule is independent of the ruling: a Plain sheet can still carry a red line, and on a Lined sheet the rule draws over the ruling. It is drawn at LineThicknessPx, centered on MarginRuleOffsetPx from the left edge, and its color’s alpha is honored.

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Punched holes

Holes are spread evenly between HoleEdgeMarginPx from the top and the same from the bottom (clamped to half the page height). A single hole centers on the sheet instead of sitting at the top margin. Each punch gets a shaded rim just inside its edge, derived from HoleColor rather than being a fixed gray, standing in for the cut edge of the stock catching less light.

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Grain

GrainStrength is multiplicative per-pixel fiber noise applied to the paper color under the ruling: printed lines sit on paper, they are not made of it. It multiplies rather than adds, so the stock keeps its hue instead of drifting gray. The default 0.04 is a barely perceptible tooth; push it to 0.15 for cheap pulp, drop it to 0 for a laser-printed sheet. GrainSeed picks which noise you get. Two documents with identical settings and different seeds get different fiber — worth setting when several notes in one scene share a look and you do not want them to be visibly the same sheet.

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How the sheet is produced

The generated texture is built once per distinct set of settings and cached on the document, so twenty pages sharing a document share one sheet. A back generated with identical settings reuses the front’s cached sheet rather than rasterizing a second copy. It is built at the document’s clamped bake size — Page Size Pixels, reduced if either axis exceeds Max Page Bake Dimension in Project Settings → Plugins → Inkwell (default 4096) — so the paper always matches the ink texture it sits behind, pixel for pixel. It carries a full mip chain generated in linear space, so the ruling does not alias or darken when the page is a couple of meters away. The sheet is transient: it lives in memory, is never saved into the asset, and is regenerated from the settings on load. Change any procedural setting and the cache hash stops matching, so the next request rebuilds it — which is why the Page Editor’s preview updates as you drag a slider.

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Recipe: lined notebook paper

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Custom material

Custom material hands the whole page material over to you. The document’s Paper Material (PaperMaterial) replaces whatever material the target slot wore — a wood desk, aged vellum, an animated hologram — and your graph carries the ink by containing the MF_InkwellPageInk material function (/Inkwell/Materials/MF_InkwellPageInk): drop it into the graph and wire your final color through it. The function carries the named parameters Inkwell drives, so every runtime control — the baked ink, Ink tint, Ink strength, face mapping onto custom meshes — keeps working inside your material. Two shipped documents are worked examples: PD_Scroll in /Inkwell/DemoProps/Documents/ uses Custom material with M_InkAgedParchment, and PD_Poster uses M_InkPosterBoard — both materials live in /Inkwell/DemoProps/Materials/ and both carry MF_InkwellPageInk. Open either material to see how little wiring the function needs. While Custom material is active (and a material is actually assigned), the paper inputs on this page do not apply: no paper texture, no generated ruling, and no per-page paper override — your material is the paper. Ink tint and Ink strength still work, and so does Paper tint if your graph chooses to use the parameter the function carries.

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Mesh’s own material

Mesh’s own material (MeshMaterial, display name Mesh’s Own Material) is the mode for props that already look right: no paper comes from Inkwell at all. The ink is laid onto whatever material the mesh already wears — Inkwell finds the target slot’s existing material per mesh instance, makes a dynamic material instance of it, and writes only the ink parameters onto that. Your per-instance textures and parameter overrides all survive; a dynamic instance already sitting in the slot (yours, or Inkwell’s from a previous page turn) is driven in place rather than wrapped or replaced. The one requirement is the same function as above: The practical difference from Custom material: with Custom material, twenty different props showing the document all get the document’s one material; with Mesh’s own material, each prop keeps its own — a carved sign, a painted wall, and a gravestone can all take the same writing while staying themselves. None of the front’s paper inputs on this page apply — texture, generated settings, per-page override: the mesh’s material is the paper. Backs stay the mesh’s own too — on a mesh with a distinct Back material slot the ink is driven onto that slot’s existing material the same way — though a Back paper of Custom material still wins and replaces that slot.

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Per-page override

Dead last in the Paper & Ink section, under the heading This page only, sits a texture picker for the page currently on screen — the page’s own PaperOverride. Set, it beats the document paper — Texture asset or Generated — for this page alone; cleared, the page goes back to the document’s paper. Use it for the one page in a journal that is a torn receipt. Flip the sheet over and the same picker reads This page’s back only and writes the page’s BackPaperOverride instead. The override is a texture, so it has no effect on a page whose paper comes from a material: under Custom material (with a material assigned) and Mesh’s own material the material owns the paper and the override is never applied to it.

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The back’s paper

A sheet’s back can wear different paper from its front. The document-level control is Back paper — it appears in Paper & Ink in place of the Paper dropdown while the Back side is being edited — backed by FInkPaperFace BackPaper on the document, whose Mode is an EInkBackPaperMode: There is deliberately no Mesh’s own material entry here — that mode already means “the mesh decides”, both faces included. Everything about the back’s paper edits through the same controls as the front’s: flip to Back and the texture picker, the generated-paper settings, and Paper tint all read and write the back’s own values (BackPaper.Texture, BackPaper.Procedural, BackPaper.Tint). While the back is Same as front there is nothing to edit — the section collapses to the one dropdown. Two more things to know:

• BackPaper.Tint is multiplied over the back’s paper the way Paper tint is over the front’s, and applies once the back declares a mode of its own.
• The back’s Custom material is slab-only. A flat single-slot mesh has one material for both faces, so its back keeps the front’s material and BackPaper.Material is ignored there. On a mesh with a distinct Back material slot — the plugin’s own page sheet is one — it applies.

Whether the back has content is a separate question from what paper it wears: layers on the back are covered in the two sides of a sheet, and an unauthored back on Same as front paper costs nothing at all.

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Paper tint, ink tint, ink strength

Three document-level controls sit under the mode-specific ones and apply whatever the mode:

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Reading paper from Blueprint

Three pure nodes on the Ink Page Document asset resolve what a page actually wears:

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The other Procedural Paper

Ink Page Display (UInkPageDisplayComponent) has a boolean also called Procedural Paper (bProceduralPaper, default true). It is a completely different thing, and the shared name is the only thing the two have in common. The component’s boolean makes the page spawn its own sheet of paper — a transient static mesh sized from the document — when the actor has no mesh of its own. Nothing on this page changes when you toggle it, and nothing on that component changes the ruling, the holes or the grain. The spawned sheet, its collision, when it steps aside for a mesh you supplied, and when to turn it off are covered under Procedural Paper on Ink Page Display.

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