Geometry effects

Turn masks into rust flakes, moss, welds or displaced geometry, then bake it back to Normal and AO.

On this page 3 sections

Geometry effects turn a layer's mask into real geometry: scattered rust flakes, moss, snow, splinters and peel fragments, a weld bead along a curve, or the material's own height displaced into mesh. Everything is an owned helper object parented to the source — you can regenerate, freeze, remove or export it, and bake it back into Normal and AO maps. The source mesh is never modified unless you explicitly ask.

Scatter effects

Select an assigned source mesh and the layer whose mask defines the density. For moss, that is the Moss effect's mask.
Open Geometry Effects › Add Geometry Effect or select a preset on the shelf. The dialog starts at a sensible density and size.
Use Regenerate, Freeze and Remove on the selected helper afterwards.

Effect	Prototypes	Material
Rust Flakes	Six jagged plates with curl and a lifted side	Dark oxide ramp with per-instance variation, lighter dust at the rim
Moss	Eight clusters of scanned CC0 Poly Haven moss_01 clump cards	The scan's diffuse, alpha, normal and roughness, translucent mix
Snow Clumps	Four displaced icospheres, squashed and sunk	Matte white with subsurface and granular bump
Splinters	Five fibrous shards with one splintered break	Stretched grain ramp along the shard
Peel Fragments	Four cracked chips rolling up from one edge	Painted face sampled from the set's base colour over a primer underside
Bolts, Scales, Rocks, Bark	Hex/round bolt heads, overlapping scale plates, angular rocks, ridged bark plates	Owned standard-node materials
Weld Curve	A bead profile with stack-of-dimes ripples along an editable curve	Metallic steel with heat tint at the toes

Each instance is aligned to the surface normal with random yaw and lean, a skewed size distribution and a variant index; materials read a per-instance random value so textures do not repeat per variant. Points are thinned to a minimum spacing, snow and moss are weighted toward upward-facing surfaces, and the published mask still rules. Card-based moss needs dense packing — use it on masked patches rather than whole objects. A 500 000-triangle project limit applies. These are instanced shapes, not simulation: snow does not accumulate by physics and placement can follow the material, while the individual pieces remain procedural or supplied prototypes.

Placement from the material

Where: What the material shows follows evaluated coverage: flakes on corrosion, peel along paint-loss borders, moss on biological growth and splinters on checking or dents. Unaged materials use available geometric cues such as edges, cavities, shade and ground proximity. Empty outcomes report Nothing to place.

Bolts on Spots puts one bolt on each blob in the active mask, sized from that blob. Whole-surface and active-mask placement are also available. Match Surface blends each piece toward the color beneath it; peel keeps a separate primer underside.

Own Pieces uses meshes from your collection as prototypes, normalized by their largest dimension. Your source meshes remain yours. Follow the Material schedules regeneration after aging changes settle; Regenerate All updates all helpers. Frozen helpers stay fixed.

The applied-effects list provides visibility and selection; its Inspector names placement, parameters and whether the effect adds geometry or changes displacement.

Material → Geometry

Action	What it does
Displace from Height	Copies the evaluated source, subdivides it (levels 0–4, simple or smooth), samples the published Height output through the set's UVs and offsets each vertex along its normal by (h − midlevel) × amplitude. The default amplitude is the set's Height Distance. Can also use the active layer's mask.
Regenerate / Apply / Replace Source Mesh	Regenerate re-copies a moved or edited source. Apply freezes the helper into real mesh data. Replace Source Mesh hands that mesh to the source — explicitly destructive.
Extract Curves	Thins the active layer's mask to its centre lines, traces paths and loops, simplifies them and projects them onto the surface as an editable curve parented to the source, split where a path leaves the surface or jumps between UV islands.
Stitches on Curve	Instances thread prototypes along a curve with spacing and size, aligned to the tangent and the nearest surface normal.
Seam Bead on Curve	A low, smooth weld profile along the curve; Weld Curve remains the rippled bead.
Bake Back to Normal / AO	Stages every generated helper of the set as a paired high-poly source (instances realised for Cycles), runs the existing bake with a ray distance covering the relief, then keeps, hides or removes the geometry. The maps read Stale when a helper regenerates.

Before/after renders and provenance for the moss scan are in docs/geometry-effects.md.