Keyline — Quick Start

1 Import and open the demo

Import the package — it lands in Assets/4ssets/Keyline/ — and wait for the compile. There is no renderer feature to add for a hard-edged outline, no volume to author and no layer to reserve. Keyline Setup opens once after the compile: pick how much of Keyline the project uses, or press Decide Later to keep everything. Two things are optional and it offers both — a soft 3D rim, and per-outline see-through layers; later they are one tick each under Project Settings ▸ Keyline ▸ Features.

Then open Assets/4ssets/Keyline/Demo/Demo.unity and press Play. Ten chapters, and the fastest way to see what the asset does. Keys 1–0 switch chapters, H hides the panel.

2 Your first outline

• Select any object with a renderer.
• Add Component ▸ Keyline ▸ Keyline Outline 3D.
• Press Add pass and choose Main Outline.
• Press New — or drag in one of the bundled profiles from Runtime/Profiles/, one per style.

That is the whole setup. The object has an outline now.

3 The four passes

One component draws up to four things, each with its own switch and its own profile:

A mesh has two more, off by default and experimental: a Cutout Overlay on the Main rim and one on the X-Ray rim, which draw that pass a second time so a hull silhouette and an alpha rim can share one object. The manual covers them; nothing here needs them.

4 A sprite instead of a mesh

A SpriteRenderer has its own component and the same everything else — the same profiles, the same styles, the same four passes.

• Select the sprite. Add Component ▸ Keyline ▸ Keyline Outline 2D.
• Add a pass and give it a profile, exactly as above.
• Under Distance Field, press Generate Distance Field.

That last step is the one that has no equivalent on a mesh. A mesh outline is an inverted hull; a sprite has no hull to push, so its rim is measured against a distance field built from the artwork’s own alpha. It is baked once, next to the texture, and from then on the outline follows what is drawn — around a hole in the middle of the sprite as readily as around its edge.

5 Drive it from code

using FourSsets.Keyline;

var outline = target.GetComponent<KeylineOutline>();

outline.MainOutlineEnabled = true;      // switch the rim on
outline.Color = Color.red;              // recolour it
outline.Width = 0.04f;                  // metres, in World width mode
outline.XRayOutlineEnabled = true;      // show it through walls too

Adding an outline at runtime is the same three lines, plus where to put them:

var outline = enemy.AddComponent<KeylineOutline>();

outline.Configure(main: hostileProfile, xray: seeThroughProfile);

Configure fills the slots in one go, which matters when you are spawning: assigning them one at a time rebuilds the outline once per slot. Showing and hiding is free either way — outline.OutlineEnabled = false takes it off screen without dismantling it, so a pooled object that stays active comes back for nothing. The Manual's Scripting chapter has short recipes for hover, selection, damage flashes, groups, pooling and more.

6 Fourteen components you do not have to write

Runtime/Recipes/ holds the arrangements people usually end up writing themselves: hover, click selection, trigger and proximity highlights, damage flashes, gauges painted on the model, impact and scan waves, materialising, squad highlighting, through-walls markers, blink, fading with distance.

They are ordinary components written against the same public API you have — every member of it is in the searchable API Reference. Add Keyline ▸ Recipes ▸ Highlight (Arbiter) plus a collider to a prop, drop Keyline ▸ Recipes ▸ Pointer Highlight (Scene) anywhere in the scene, and hovering works — one raycast per frame for the whole scene, nothing registered, nothing wired.