Intersection Glow

Intersection Glow highlights the contact line between a transparent mesh and the opaque world behind it — the classic force-field-bubble effect. Genesis samples the depth buffer and lights up pixels whose depth is close to the geometry beneath them.

Video

A transparent force-field bubble moving across uneven terrain, with a bright cyan HDR glow tracing the contact line wherever the bubble intersects the ground and props.

features/intersection-glow/intersection-forcefield.mp4

A bright contact line tracking where the force-field bubble meets the world.

When to use it

Force-field bubbles around characters or buildings.
Water surfaces — a bright foam line where water meets shore or props.
Magic barriers — a bright contact glow where the wall meets the ground.
Bullet impacts — a short-lived intersection between a sphere and the hit surface.

Difference from Rim Lighting

Rim Lighting uses the surface normal against the view direction, lighting silhouettes. Intersection Glow uses a depth comparison, lighting the line of contact with other geometry. Force-field bubbles often use both.

How it works

The shader samples _CameraDepthTexture, computes linearSceneDepth - linearSurfaceDepth, and remaps it into a 0–1 weight via pow(1 - depthDelta / _IntersectionWidth, _IntersectionPower). The result is multiplied by _IntersectionColor * _IntersectionIntensity and added to the lit output.

Transparent sphere reads as a flat alpha-blended hull.

A bright cyan line where the sphere meets the floor, fading inward over 0.3m.

Plain sphere

Intersection glow · cyan HDR

A plain transparent hull against one with intersection glow. Drag to compare.

Properties

Inspector label	Shader property	Type	Default	Description
Glow Color	_IntersectionColor	Color (HDR)	RGB(0.3, 0.9, 1.0)	HDR glow tint.
Width	_IntersectionWidth	Float (0–2)	0.25	World-space distance over which the glow fades.
Power	_IntersectionPower	Float (0.1–8)	2.0	Sharpness of the falloff curve.
Intensity	_IntersectionIntensity	Float (0–8)	2.0	Overall multiplier; go HDR for bloom.
Noise Texture	_IntersectionNoise	Texture2D	None	Optional noise to break up the line.
Noise Scroll	_IntersectionScroll	Vector4	(0, 0.2, 0, 0)	UV scroll for the noise, creating flowing energy.

Usage

Enable Depth Texture on the URP Asset (required).
Switch the material to Transparent.
Enable Intersection Glow and pick a color. HDR intensities of 2–6 sell the effect through Bloom.
Add a scrolling noise texture for energy flowing along the edge.


material.SetColor("_IntersectionColor", new Color(0.3f, 1.0f, 1.0f) * 4.0f);
material.SetFloat("_IntersectionWidth", 0.3f);
material.SetVector("_IntersectionScroll", new Vector4(0.5f, 0.2f, 0, 0));

Tips & gotchas

The depth texture must be enabled, or the glow is invisible.
Transparent geometry does not write depth, so two intersection-glow meshes cannot detect each other.
On Android with MSAA, depth-resolve copies cost; disable MSAA or use the Forward+ resolve path.
Width is in world units, so scale it with the camera distance if your views vary widely.

Depth Coloring — also reads scene depth.
Hologram — pair for the canonical sci-fi shield.
Emission — the glow feeds the same bloom pipeline.
See-Through — silhouette through walls.