Prepare modular meshes

You can learn the whole plugin on the example content - come back here when you bring your own kit. Spline Architect compensates for imperfect meshes, but a consistent kit means cleaner corners, fewer overrides, and less time spent wondering why one piece sits wrong.

Coordinate contract

Axis	Wall and Curve convention
X	Piece length: the direction that follows the spline.
Y	Piece depth or profile width. Positive Y is the actor's outward/right side.
Z	Height.

Place the pivot at a repeatable connection point. For a wall piece, a bottom corner or bottom center is usually easiest. Corner meshes need a pivot that matches the intended bend or miter center. Spline Architect fits from asset bounds, so remove hidden collision helpers or stray vertices that inflate those bounds.

Build a useful kit

• At least one straight Wall mesh with a known natural X length and Z height.
• Optional shorter straight pieces for Best Fit packing.
• Optional filler pieces for small residual gaps.
• A corner mesh if the preset uses a mesh-driven corner.
• Door, arch, or gap assets for Custom Pieces.
• Post meshes for corners, spline points, starts/ends, or periodic placement.
• Materials that expose consistent scalar/vector parameters if presets will randomize them.

Scale and dimensions

Author at Unreal scale: 1 Unreal Unit = 1 centimeter. When Wall Length, Wall Height, or Corner Length overrides are off, Spline Architect derives them from mesh bounds. Turn an override on only when logical dimensions should differ from the raw asset.

Use Keep World Scale when a piece must retain its authored proportions. Otherwise generation scales pieces to the resolved slot and height. Custom Wall Mesh entries can define explicit pivot-relative logical Bounds Min XZ and Bounds Max XZ for an asset whose visual bounds are not its fitting bounds.

Materials, Nanite, collision, and lightmaps

• Keep material slots stable across variants if they share preset material overrides.
• Nanite is compatible with generated and baked static meshes, subject to the normal Unreal limitations of the output component type.
• Configure source collision for repeated static pieces. Newly collapsed static meshes should be checked after conversion.
• For baked/static lighting, enable generated lightmap UVs in Project Settings or use the Lightmap Tool.

What PCG measures a prop by

The SA prop pools measure an asset by its visible bounds, not its collision. A prop with tight or missing collision still reserves the room its mesh occupies, which is what keeps packed placement and footprint pruning honest.

For a Blueprint prop, every visible component counts: static and skeletal meshes, instanced meshes and all their instances, shapes, and any child actor's own geometry. Editor-only visualizers such as arrows and billboards are ignored. A Blueprint with no visible geometry at all falls back to a small placeholder box, so a prop that packs suspiciously tightly is usually one whose geometry is spawned at runtime rather than present in the class.

Fix a pivot without leaving Unreal

Select one or more Static Mesh assets and open Spline Architect → Pivot Tool. Choose Min, Center, Max, or Keep per axis, decide whether to overwrite or create suffixed assets, then apply. See Pivot Tool for every option.