User Guide

Overview

PropMaster PCG is three dressing tools for Unreal Engine 5.8 that turn a blockout into a dressed scene in minutes. Each tool is a Blueprint you drag into the level, fill with meshes, and tune from its Details panel.

Tool	Blueprint	Use it for
Spline	BP_PCG_PropMaster_Spline	Paths, walls, fences and pipes along a spline, or scatter filling a closed spline area
Volume	BP_PCG_PropMaster_Volume	Dressing a box: floors, walls and ceilings of a room, or the outside of rocks and props inside it
Mesh Cover	BP_PCG_PropMaster_CoverMesh	Growing moss, vines, debris and decals over meshes already in the level

All three share the same building blocks: layers of main meshes, Cluster Mesh around them, Cover Mesh by Intent on top of them, Decals, an Optimize section and the Footprint cost readout.

Your first result

Find the Blueprints under PropMasterPCG Content > Tools and drag one into the level.
Shape it: move the spline points, or scale the volume box over your area.
In Prop Master, open layer Index [0] and add a mesh under Spawning > Static Meshes.
Click Refresh under PCG Controllers. The tool regenerates by itself after most edits; Refresh forces it.
Add more layers for more kinds of meshes. Later layers can avoid what earlier layers placed.

Panel basics

Every tool's Details panel has the same top-level sections, in this order. Collapsing a layer and opening it again folds its sections, so long panels stay easy to scan.

Section	Setting or button	What it does
Selection	Hide Selection Outline	Removes the orange selection outline from the spawned meshes while the tool is selected, so you can judge the look. It comes back when deselected.
Prop Master / Mesh Cover	Layers (Prop Layers, Mesh Cover Layers)	The list of layers this tool spawns, in order. Each layer is one kind of dressing. Later layers can avoid earlier ones.
Layer	Layer Title	The name shown on the collapsed layer and in front of its sections.
Layer	Mute	Skips the layer without losing its settings.
Layer	Solo	When any layer is soloed, only soloed layers generate. Use it to tune one layer at a time.
Seed	Global Seed	Offsets every random choice in the tool.
Seed	Randomize Global Seed	Picks a new random Global Seed and regenerates.
Footprint Controllers	Update Footprint, Measure GPU Cost, Set Baseline, Clear Baseline	Cost readout of what the tool made. See Footprint.
PCG Controllers	Refresh	Rebuilds the layers and regenerates. Use it after editing a preset asset, or on the Mesh Cover tool after moving the meshes it covers.
PCG Controllers	Convert to Mesh	Bakes the spawned meshes into a new plain actor where they are, and switches the tool's PCG off so nothing spawns twice.
PCG Controllers	Disable PCG / Enable PCG	Removes the spawned meshes and stops regenerating, or switches it back on and regenerates.
Preset Controllers	Presets	Preset assets whose layers are added to this tool's own at generation time.
Preset Controllers	Save as Preset	Saves all layers into a new Preset asset, ready to add to another tool of the same kind.
Preset Controllers	Edit Presets	Copies every preset's layers into the tool's own layers, where you can edit them, and empties the Presets list.
Generated (advanced)	Warnings	Plain-language problems from the last build, such as an empty mesh list or a tag no actor has. Check it first when something does not spawn.

Most changes regenerate on their own. Every random choice is seeded, so the same settings always give the same result.

Spline tool

The Spline tool places meshes along a spline or fills the area inside a closed spline. Each layer runs through the sections below, top to bottom.

Spawning: what gets placed

Setting	What it does
Activate Main Mesh	Spawns this layer's main meshes. Off skips them; clusters and cover can still run.
Static Meshes	The meshes picked for each point. Each entry has a Weight (2 = picked twice as often as 1, 0 = never).
Static Meshes > Add Tag	Tags the spawned meshes, so other tools' tag filters can see them (for example, keep another spline's clusters off them).
Static Meshes > Local Transforms	This mesh's own offset, rotation and scale, to fix off-centre pivots, wrong facing or mismatched sizes. Random Rotation Steps turns it by whole steps (90 = quarter turns) for modular pieces that must stay square.
Static Meshes > Forward Axis	The mesh axis that runs along the spline, for Grammar and Mesh Along Spline.
Grammar > Use Grammar	Lays the meshes end to end along the spline in a pattern of their Symbol letters instead of scattering. Along the spline only. The Cheat Sheet in the panel shows the pattern syntax.
Actors	Blueprint actors picked at random alongside the meshes (each counts as Weight 1). They are real actors, so keep counts modest.
Mesh Bounds Modifier	Grows or shrinks the layer's footprint (width and length only) for its clusters, tag filters and later layers' overlap checks.
Tags	Spawn Only On Tag / No Spawning on Tag with a bounds modifier each: spawn only on, or never on, actors and meshes carrying a tag.
Overlap	No Overlap of Previous Index Spawns / Clusters: keeps this layer clear of the layers above it.

Distribution: where and how many

Setting	What it does
Spawn Inside Spline	On fills the closed spline's area. Off places along the spline, where Mesh Along Spline and Grammar are available.
Density	Percent of candidate points kept.
Distance	Spacing between candidate points.
Use Count / Count	Spawns an exact number of points instead of using Distance.
Clump Together	Gathers meshes into patches. Clumping 0 = even scatter, 1 = tight clumps. Clump Size sets the patch size, Clump Pull moves points toward the patch centre and Min Spacing pushes them apart again.
No Overlapping	Removes meshes whose bounds overlap another of this layer (one survives).
Stack Vertical	Stacks rows of each mesh. See below.
Distribution Seed	Re-rolls this layer's point pattern.
Inset Within Closed Spline (inside only)	Inset Min keeps points away from the edge; Inset Max keeps only a band along the edge. Both are shares of the way to the centre.
Start and End (along only)	Fit to Curve adjusts spacing to fit the spline exactly. Start / End Offset leave the ends empty.
Activate Mesh Along Spline (along only)	Bends one mesh along the whole spline (pipes, fences, curbs) instead of scattering. Mesh Along Spline Scale sets its thickness.

Stack Vertical

Stack Vertical builds rows of each mesh on top of itself. Along the spline it makes a wall; inside the spline each point becomes its own pile. Rows always sit on the real size of the mesh below, and a tilted piece makes a stack that leans with it.

Setting	What it does
Activate	Turns stacking on for this layer.
Rows Min / Rows Max	Rows per stack, counting the bottom one. Each stack picks a count in this range.
Row Gap	Positive leaves a gap; negative sinks rows into each other (rocks, sandbags).
Stagger	Wall: every other row slides along by this share of the mesh length (0.5 = brick pattern). Pile: each row shifts and turns a little at random.
Row Rotation	Each row turns this many degrees further than the row below. 90 = log-cabin crossing; small values twist the stack.
Taper (walls only)	Each row is this much smaller than the one below (0.1 = 10%), for sandbag or dry-stone walls.
Keep Stacking Chance	Above Rows Min, the chance a stack goes on to the next row. Below 1 gives a ragged top or piles of different heights. Nothing ever floats.

Cover Mesh by Intent puts Top cover only on the top piece of each stack and Bottom cover only on the bottom row. It is not available with Mesh Along Spline. Actors stack too: their size comes from the Blueprint's static meshes, so a set with tall parts (poles, lamps) stacks on its tallest part; use a negative Row Gap to pull those rows down.

Transforms

Setting	What it does
Jitter	Randomises where each point lands inside its spacing cell. 0 = exact spacing (lights, fence posts), 1 = anywhere in the cell.
Global Position / Rotation / Scale	Applied to every mesh in the layer.
Offset Position / Rotation / Scale Min and Max	A random amount between Min and Max per mesh, per axis. Uniform Scale uses only X.
Keep Inside Spline / Keep Inside Margin	Inside the spline: a mesh pushed outside by the offsets gets a new or smaller offset, and is only dropped if its own spot is outside. Margin keeps big meshes from hanging over the edge.
Absolute Rotation	Uses Global Rotation as the final rotation instead of following the surface.
Offset Seed	Re-rolls the random offsets.

Projection: landing on the ground

Projection drops each point onto the surface below it. Main Mesh and Clusters have the same settings, each on its own.

Setting	What it does
Activate Projection	Projects onto the surface. Off keeps the spline's own height.
Projection Type	Default, Mesh Only, Landscape Only, or Landscape and Mask Mesh: which surfaces the ray may land on.
Use Landscape Heightfield	Much faster than rays on landscapes, when there is no snap limit or slope range.
Align to Surface	Tilts each mesh to the surface.
Snap to Surface Max Distance	Drops points whose surface is farther than this. 0 = no limit.
Surface Angle Min / Max	Steepness allowed, in degrees: 0 = flat, 90 = vertical, 180 = ceiling. 30 to 40 keeps meshes off steep hills.
Projection Height and Depth	Where the ray starts above the point and how far below it reaches. Lower them to land under a bridge or roof.
Overhang Cleanup	0 = off. 1 removes any mesh hanging past the edge of its surface; 0.5 needs half of its footprint supported.
Landscape Layers	Only On / Never On Landscape Layer by paint layer name, with a weight Threshold and a Clearance ring checked around each mesh (keeps tree canopies off roads).

Cluster Mesh: smaller meshes around each main mesh

Setting	What it does
Activate Cluster Mesh	Spawns clusters around each main mesh.
Meshes	Cluster meshes with a Weight each.
Amount & Size	Density (percent), Density at Max Distance (thins toward the edge), Chance to Cluster (share of main meshes that get one), Size (half-size in cm) and Distance Scale Amount (scale at the edge).
Clump Together, Seed	Same as Distribution, for the clusters.
Transforms	Cluster position, rotation and scale offsets, plus Keep Clusters Inside with its margin.
Around the Main Mesh	Main Object Tightness pushes clusters away (positive) or lets them closer (negative). Follow Main Mesh removes a cluster when its main mesh is removed. Distance from Main Mesh caps how far clusters reach.
Overlap	No Overlap keeps cluster meshes apart, with a Bounds Override.

Decals

Setting	What it does
Activate Decals / Decal Materials	Turns decals on. Materials must use the Deferred Decal domain. Each decal is an actor.
Decals On Top of Meshes / Decal Chance	Adds decals at a share of the spawn points, on top of the meshes. Off mixes decals in with the meshes instead.
Decals Only (Clear all Meshes)	This layer spawns only decals.
Cluster Decals	Decals on the cluster points, on top of or instead of the cluster meshes, with their own chance.
Transforms	Decal Size (X = projection depth), random scale and spin.
Rendering	Decal Fade Screen Size and Decal Sort Order.
Max Decals	Caps the decal count. Thousands of decal actors get slow. 0 = no limit.

Optimize

Main Mesh, Clusters and Cover Mesh by Intent each have the same switches.

Setting	What it does
Cull Distance Start / End	Fades meshes out between these distances. 0 = never culled.
Receives Decals	Off keeps decals off these meshes (turn off for trees and grass).
World Position Offset	Off stops wind animation. Saves GPU on large counts and fixes blinking shadow blobs.
Visible in Ray Tracing	Off makes Lumen and ray tracing ignore them. Helps dense grass that shows dark blotches.
Cast Shadow	Off: no shadows. A big saving for grass, pebbles, debris and moss.
No Collision (main, clusters) / Collision (cover)	Main and cluster meshes can drop collision to save memory. Cover meshes have none unless you turn Collision on.

Debug

Work in Debug Mode runs every placement step but spawns nothing, so regenerating is fast. The Show switches draw debug boxes for main, cluster and cover bounds, and shade slope ranges from white (Min) to black (Max).

Volume tool

The Volume tool casts a grid of rays across a box and dresses the surfaces they hit. Spawning, Transforms, Cluster Mesh, Decals, Cover Mesh by Intent, Optimize and Debug work as in the Spline tool; this section covers what is different.

Projection (top of the panel)

One setting for the whole tool, above Prop Layers.

Option	Rays start	Use it for
Inside a Room	On the centre of the box, going out to each side	Floors, walls and ceilings of a room, and anything inside it
Around Objects	On the far side of the box, crossing it	The outside of rocks, ruins and props placed inside the box

Faces: which surfaces get dressed

The box shows the labels Up, Down, Left, Right, Front and Back. Each checkbox names the way the covered surfaces face, so it means the same thing in both Projection modes.

Checkbox	Covers	Inside a room this is
Up-Facing Surfaces	Floors, ground and the tops of objects	The floor
Down-Facing Surfaces	Ceilings and the undersides of objects	The ceiling
Left-Facing Surfaces	Surfaces facing the Left label	The Right wall
Right-Facing Surfaces	Surfaces facing the Right label	The Left wall
Front-Facing Surfaces	Surfaces facing the Front label	The Back wall
Back-Facing Surfaces	Surfaces facing the Back label	The Front wall

The same section holds Main Mesh / Cluster Overhang Cleanup (0 = off, 1 = remove anything hanging past its surface's edge) and Minimum Surface Width, which keeps main meshes off ledges and rims narrower than the width you set.

Distribution

Setting	What it does
Density	Percent of rays kept.
Use Count / Count	An exact number of rays spread over the chosen faces.
Width and Height Controls	Width / Height Spacing = exact distance between rays on each face. Min / Max (0 to 1 of the box) limit rays to a band, for example only the lower half of the walls. Width / Height Scale grow or shrink meshes across the face.
Main Surface Angle Min / Max	World slope allowed: 0 = flat floor, 90 = vertical wall, 180 = ceiling.
Max Surface Angle	How far a hit surface may tilt away from the face direction and still be used.
Align to Surface	On: meshes stand out from the surface they hit. Off: they keep the face direction as up.
Clump Together, No Overlapping	Same as the Spline tool. Keep Clump Pull low on uneven walls.
Stack Vertical	Piles on every face, growing straight out of the surface: up from floors, sideways out of walls, down from ceilings. Taper is hidden (piles only).

Volume-only Transforms

Setting	What it does
Surface Facing Axis	Which side of the mesh faces out of its surface (floor, wall or ceiling alike), keeping the mesh upright on walls. Use it instead of a Global Rotation to stand pieces up.
Random Rotation Steps	Turns each mesh by whole steps around its own axis (cliff pieces, tiles, crates).
Offset From Surface	Moves meshes out from the surface (positive) or sinks them in (negative).
Keep Inside Volume / Margin	Drops meshes (and their clusters) pushed outside the box by the offsets.

Volume limits and debug

Max Rays (advanced) is a safety limit on all rays in the tool. Tiny spacing on a big box makes a lot of rays, so raise it carefully.
Max Cluster Points (per layer) (advanced) lowers a layer's Cluster Density for the build, with a Warning, when it would make too many candidates.
Optimize > Main Mesh > Ray Layers: more than 1 adds extra starting planes, so surfaces hidden behind nearer geometry get reached too.
Debug > Show Ray Hits draws a small box where each ray hit and a large one where it missed, to show blocked areas.

Mesh Cover tool

The Mesh Cover tool dresses meshes that are already in the level: rocks, cliffs, ruins, or the Spline and Volume tools' own spawns. Each Mesh Cover Layer picks its targets, then places Cover Mesh by Intent entries and decals on them.

Targets: what gets covered

Setting	What it does
Target Actors	Placed actors picked with the eyedropper or drop-down. Every static mesh on them is covered, wherever they are.
Target Meshes	Static meshes to cover by asset. Empty = every mesh inside the Spawn Only On Tag area.
Search Entire Level	Off: only meshes whose centre is inside the tool's box. On: the whole level (loaded World Partition cells only).
Include Instances	Also covers instanced meshes such as foliage and the Spline and Volume tools' spawns, not just Static Mesh actors.
Target Size Min / Max	Skips targets smaller or larger than this (largest side, as placed). 0 = no limit.

Layer contents

Section	What it does
Cover Mesh by Intent	One entry per cover style (moss, vines, debris), each with its own Top / Side / Bottom, Facing and Tags. See Cover Mesh by Intent.
Decals	Activate Decals, Decal Materials, Decal Chance (share of cover points that get one), Decals Only (No Cover Meshes), Transforms (size, scale, spin), Rendering and Max Decals.
Optimize	Cull distances, decals, wind, ray tracing, shadows and collision for the cover meshes.
Debug	Work in Debug Mode, Show Cover Mesh Bounds and Show Cover Slope.

Max Targets (per layer) is a safety limit on how many targets a layer may ray-trace. The tool does not notice when you move the meshes it covers: click Refresh after moving them.

Cover Mesh by Intent

Cover Mesh by Intent grows smaller meshes over the main meshes (in the Spline and Volume tools) or over the targets (in the Mesh Cover tool). Each entry is one cover style, such as moss, vines or debris. Entries never repeat each other and never space out against each other.

Entry settings

Setting	What it does
Layer Title	The entry's name, shown on the collapsed entry and in front of its sections.
Activate	Master switch for the entry. Off places nothing but keeps Top, Side and Bottom as they were.
Facing	Covers only the side facing a direction. Facing Arrow = the tool's forward direction (the Mesh Cover tool shows an orange arrow). Face Toward Actor = surfaces turned toward a picked actor. Max Angle sets how far a surface may turn away.
Top / Side / Bottom	The three cover categories, below.
Tags	Spawn Only On Tag / No Spawning on Tag areas for this entry. Tagged splines make a strip; Spline Path sets its width at each end (taper), Edge Jitter, Jitter Scale and Edge Softness. Other tagged actors use their bounds, grown or inset by Mesh Bounds Modifier.
Cover Seed	Re-rolls this entry's cover.
Clear Cover Inside Meshes / Clearance	Removes cover buried in or pressed against another surface, checking Clearance cm out from each point.

Top, Side and Bottom

Top covers up-facing surfaces, found by rays cast down. Side covers the object's sides with sideways rays. Bottom covers the base, like moss creeping up from the ground. Each category has its own copy of these settings.

Setting	What it does
Activate	Turns this category on.
Copy to Other Categories	Copies this category's meshes and settings into the other two, keeping their Activate and Height. Unticks itself.
Meshes	Cover meshes picked at random. Empty = nothing spawns.
Density	How tightly the surface is covered. 100 = a candidate every 45 cm.
Chance of Covering Object	Chance that each object gets this category at all.
Cover Spacing	Minimum distance between two cover meshes of this category. 0 = off.
Clump Together	Gathers the cover into patches, with Clump Pull and Min Spacing.
Transforms	Jitter, Position Offset (X and Y slide along the surface, Z lifts or sinks), Absolute Rotation, Rotation and Scale Min / Max.
Align to Surface	The mesh's up axis follows the surface. Off keeps it upright.
Flip Z Axis	Hangs the meshes straight down from where they touch, for moss or vines dangling from a ledge.
Height Min / Max	The band of each object to cover, in percent of its height (0 = bottom, 100 = top). Defaults: Top 66 to 100, Side 33 to 66, Bottom 0 to 33.
Cover Scale By Height	Scale at Height Max (x1 at Height Min). 1 = off.
Surface Angle Min / Max	Steepness to cover: 0 = tops, 90 = sides, 180 = undersides.

Optimize > Cover Mesh by Intent holds the cull distances, decals, wind, ray tracing, shadow and Collision switches for every entry of the layer. Cover meshes have no collision unless Collision is on.

Footprint

The Footprint section, under Footprint Controllers, shows what the tool made and what it costs. It updates by itself after every generate. Notes and Changes sit at the top: Notes flags likely problems, and Changes shows how far each number moved.

Buttons

Button	What it does
Update Footprint	Recounts now.
Measure GPU Cost	Renders a couple of seconds from the current viewport with the tool shown, then hidden, and records the difference. Measure from the same spot before and after a change.
Set Baseline	Remembers the current numbers. Changes then compares every later update to them, which suits an optimize pass.
Clear Baseline	Forgets the baseline; Changes compares with the previous update again.

The numbers

Group	Number	What it means
Rendering	Instances	Mesh instances this tool spawned.
Rendering	Mesh Components	About one per mesh and settings combination; each is at least one draw call per pass. Fewer is better.
Rendering	Unique Meshes	Different mesh assets in use.
Rendering	Nanite / Non-Nanite Instances	Nanite stays cheap when dense. Large non-Nanite counts are the usual performance trap: enable Nanite or add cull distances.
Rendering	Non-Nanite Triangles (LOD 0)	The worst case up close.
Rendering	Shadow-Casting, WPO-Animated, Ray-Traced Instances	How many instances the matching Optimize switches leave on.
Rendering	Decal Actors, Other Spawned Actors	Each is a full actor. Keep decals in the hundreds, not thousands.
Memory	Instance Memory (MB)	Transforms, render data and collision bodies for these instances.
Memory	Instances With Collision	Each carries a physics body. Optimize > No Collision removes them.
Memory	Mesh Assets (MB)	The mesh assets used, shared with anything else using them. Textures and materials are not counted.
Loading and Streaming	Instance Data on Disk (MB, est.)	Roughly what the level has to read when this tool loads.
Loading and Streaming	Mesh Files (MB, editor)	Mesh asset file sizes in the editor. Cooked builds are usually smaller.
Loading and Streaming	Tool Size (m)	Width and length of everything spawned. With World Partition, one big actor loads all its instances at once.
Loading and Streaming	Spatially Loaded, PCG Partitioned	Whether World Partition streams the tool by distance, and whether the PCG output is split into cells.
Loading and Streaming	Last Generate (s)	How long the last full generate took in the editor.
GPU Cost	GPU Cost (ms), Share of Frame (%), FPS With / Without Tool	Set by Measure GPU Cost. Measured says when, and whether the tool has changed since.

Meshes (most instances first) lists the heaviest meshes, so you know where to start optimizing.

Tips and troubleshooting

Keep it fast

Turn off Cast Shadow on dense small meshes (grass, pebbles, moss). It is usually the biggest single saving.
Turn off World Position Offset and Visible in Ray Tracing on dense grass and ground cover.
Add Cull Distance Start / End to small meshes; use Nanite meshes where you can.
Use Solo to tune one layer at a time, and Work in Debug Mode while dialing in placement.
Watch Decal Actors and Max Decals: every decal is an actor.
Use Set Baseline before an optimize pass and read Changes after each tweak.

When something looks wrong

Symptom	Check
Nothing spawns	Warnings first. Then Activate Main Mesh, an empty mesh list, Mute / Solo, and Density.
Meshes float or sink	Projection Type, Snap to Surface Max Distance, Projection Height and Depth; in the Volume tool, Offset From Surface.
Meshes don't follow the slope	Align to Surface on, and Absolute Rotation off.
Meshes on roads or paths	Never On Landscape Layer with a Clearance ring, or No Spawning on Tag on the road spline.
Volume dresses the wrong side	Check Projection (Inside a Room or Around Objects), then the Faces checkboxes against the labels on the box.
Mesh Cover finds nothing	Targets: box placement, Search Entire Level, Include Instances, Target Size Min / Max. Click Refresh after moving the covered meshes.
Cover buried in walls or floors	Clear Cover Inside Meshes with a larger Clearance.
Stacks too far apart or overlapping	Row Gap (negative sinks rows together).