SLatHarmony: Locality-Guided Harmonization for Local 3D Editing

Local 3D editing requires faithfully realizing the intended changes within the target region, preserving non-edited regions, and maintaining coherent shape and texture across the entire asset. Existing methods typically mitigate non-target changes through constrained generation or inversion-based editing. In contrast, we leverage the spatial locality of the structured latent (SLat) representation in TRELLIS.2 to combine source and edited SLat fields through regional composition, thereby preserving source content outside the target region. However, achieving coherent shape and texture integration between target and non-edited regions remains challenging. We therefore propose SLatHarmony, a framework that couples regional SLat composition with cross-field harmonization. Specifically, a shape SLat seamer predicts locally decodable transition features using context from the source and edited sides to bridge geometric discrepancies near the interface, while a texture SLat harmonizer combines channel-wise field alignment with boundary-aware target-region correction to reduce appearance mismatch. Experiments on Edit3D-Bench show that SLatHarmony substantially improves the preservation of non-edited geometry and appearance while maintaining competitive semantic alignment with the edit instruction.