PRG V4.0 Changelog

Prepared October 23, 2026 · Unreal Engine 5.4–5.8 · Win64

V4.0 improves generation quality, surface traversal, bark shading and growth playback, and adds cave roots, hanging vines and organic bridges. Existing V3 features such as VAT export, Climbing/Wrapping profiles, barriers and attraction fields are retained.

V4 documentation · Download Markdown

New growth modes

• Added Hanging vines that start from a supported underside or ledge, traverse the anchor surface, descend into free spans and can reattach to nearby walls or floors.
• Added Cave / Underground roots for interior cave ceilings and walls, with ceiling traversal, wall descent, lateral weave, optional floor runners and terminal floor embedding.
• Renamed the former Burrowing display label to Cave / Underground while preserving the saved enum value and existing preset references. This mode starts inside the cave; it does not tunnel from terrain above it.

Organic bridges and attached details

• Added the Organic Bridge authoring workflow with four editable bank anchors, left/right guide paths, root/vine/hybrid styles, structural rails, primary bundles and secondary/tertiary weave.
• Added working bridge runtime export with growth from End A to End B, End B to End A, or Both Ends to Middle. The exported runtime actor can change the starting bank without rebuilding the authoring mesh.
• Improved bridge landing curves and assigned MI_AlderRoot as the default structural material instead of the old white placeholder.
• Bridge runtime export now hides the fully grown source and suppresses its shadows, including after reopening the map. Build Bridge restores the source for editing.
• Added shared detail-attachment workflows for Root, Vine and Bridge: weighted mesh variants, placement rules, spacing and filters, exclusion regions, optional atlas selection and growth-timed instancing.

Spline paths and surface traversal

• Improved root/vine starts so supported stems emerge from the surface and join the actual finalized path, reducing launch bends that leave the wall and double back.
• Improved wrapping-vine travel on flat surfaces and across edges, climbing branch launch directions, supported corner transitions and downward Surface-root traversal.
• Reduced angular small-branch paths and repetitive zigzags with curvature-aware sampling and smoother, radius-aware turns. Authored spline controls are retained in the mesh path cache.
• Improved child attachment placement and boundary handling so attachment geometry does not extend behind the child start through the opposite side of its parent.
• Added support-sidedness checks for solid meshes and thin surfaces, plus safer handling of unsupportable tight return bends.
• Improved Barrier strand curves and endpoint-preserving sampling to reduce sharp control-polyline corners.

Tube geometry, smoothing and tips

• Fixed a demonstrated cotangent-smoothing instability that could create very large spikes near thin branches and endcaps.
• Strengthened local fold, ring-clearance and cross-section checks against ribboning, twisting and severe pinching on both small and large tubes.
• Limited smoothing displacement relative to the tube radius and improved bend handling to retain body thickness through surface transitions.
• Added a longer, pointed terminal taper and continuous endcap texture/shading frames, replacing blunt root endings and visible cap-direction bands.
• Improved vine anchors and fibers with gradual curvature, better relative thickness, tapered tips and partially embedded contact ends. Anchor direction follows local growth rather than fixed world-down.

Bark mapping, normals and junctions

• Reworked radius-aware texture mapping around the measured tube cross-section, keeping bark density more consistent on narrow and deformed tubes.
• Added Bark Detail Radius Exponent across Root, Vine, Barrier and Bridge. The default 0.25 gives moderately finer bark features as radius decreases; zero keeps approximately constant physical feature size.
• Added localized parent-to-child texture and surface-normal transfer, including both attachment ends of bridge strands. Junction Texture Blend Strength controls the inherited contribution.
• Improved normal-map composition, small-tube precision and static-export vertex-color encoding so the saved shading payload is interpreted correctly.
• Added optional geometric junction fusion across the four mesh generators. Fusion defaults to off because it can substantially increase build time and triangle count; texture blending works independently.

Growth playback, Sequencer and proximity

• Improved forward/reverse playback, VAT frame-boundary interpolation and loop/ping-pong endpoint timing. Unused frame time carries into the next cycle instead of causing a boundary pause.
• Verified direct Growth Progress property tracks across Root, Vine, Barrier and Bridge exports. Sequencer keys control timing directly and bypass autonomous easing.
• Fixed proximity activation for Characters already inside the trigger at Begin Play, repeated-overlap behavior and one-shot activation after stopping. Reset Growth explicitly rearms a one-shot trigger.
• Improved runtime material-instance ownership after cache invalidation and VAT frame reduction around changing cross-section rotation and radius.
• Added bridge directional timing through export, runtime preview, Sequencer and attached-detail growth, including restoration of the complete authored surface at full progress.

Editor, export and installation

• Fixed the PRG tools tab following editor actor/component selection, including switching between Root, Vine, Barrier and Bridge layouts while open.
• Improved mesh-only rebuild and Static Mesh export fidelity so existing authored paths and finished preview geometry are retained where applicable. Failed builds no longer leave a partial result marked ready to export.
• Updated current Growth Data to mesh payload version 7 with eight UV layers. UV5/UV6 retain centerline-collapse data; the additional mapping supports physical bark scale and junction transfer.
• Recreated all five distributed actor Blueprint packages from their current native parents in each supported engine version, preserving asset paths, defaults, presets and materials.
• Added a repeatable developer refresh workflow that recreates the wrappers in an independent content-only project and verifies compilation, owned components, generation, saved-map reload and final installation.

Engine compatibility and verification

• Expanded the supported Win64 editor installations from UE 5.6-5.7 to UE 5.4, 5.5, 5.6, 5.7 and 5.8, with separately built native modules and engine-native content.
• Matched shared implementation, PRG defaults and material parameters across the five versions. Material/function portability now handles already-converted Interchange paths without nesting the plugin prefix again.
• Verified 49 native PRG tests and 108 Python/source/report tests per engine, 85 content assets and 20 compiled materials/instances. Saved runtime/Sequencer examples and all 25 recreated actor Blueprints were checked after reopening.
• Locked seeds remain deterministic for matching inputs within a tested engine. Engine collision differences and the corrected sampling can change regenerated paths, branch counts and topology between versions or relative to V3.

Upgrading from V3

• Install the package built for your Unreal Engine version, with the editor closed. Do not copy a newer engine's .uasset files into an older project.
• Back up the project and any customized plugin content. Existing actor/preset paths and the saved Burrowing enum value are preserved.
• Use Build All on Root/Vine actors, Build Now on Barrier actors or Build Bridge on bridges to obtain the corrected paths. Build Mesh only updates geometry from the paths you already have.
• Regenerate Static Mesh and runtime Growth Data exports to obtain V4 geometry, texture mapping and bridge directional timing. Preserve old exports if their exact appearance must remain unchanged.
• Re-export existing bridges before using Bridge Growth Mode. Reversing Growth Direction retracts a bridge; it does not choose the opposite starting bank.
• Keep fusion off for normal iteration. Enable it only for a measured final bake when a connected junction mesh is needed.

Behavior and limits

• VAT and Material / Shader playback both remain available for Root, Vine and Barrier. Bridge runtime export uses Material / Shader growth.
• Hanging vines are generated mature shapes with growth playback, not a live rope, wind or physics simulation.
• The built-in proximity trigger accepts ACharacter overlaps and is centered at the runtime actor origin. Other Pawn or prop policies need a Blueprint/code trigger.
• Parent texture transfer needs the parent surface in the combined mesh. Individually exported or split branches cannot transfer texture across separate files.
• Irregular collision, extreme radius/spacing settings, custom shaders and project-specific sequences still need scene testing. Verification covers Windows editor and runtime automation, not a new packaged-game or other-platform certification.