SceneExpander: Text-Guided 3D Scene Expansion via Free-Form View Insertion
Organizations: Sun Yat-sen University · KlingAI Research, Kuaishou Technology
Abstract
World building with 3D scene representations is increasingly important for content creation, simulation, and interactive experiences, yet real workflows are inherently iterative: creators repeatedly extend existing scenes under user control. Motivated by this gap, we study text-guided 3D scene expansion via free-form view insertion. Starting from a real scene captured by multi-view images, a user specifies a text expansion intent, which a generative model materializes as an inserted view extending the scene coverage. Unlike simple object editing or style transfer within a fixed scene, the inserted view may be 3D-misaligned with the original reconstruction, introducing geometric shifts, hallucinated content, or view-dependent artifacts that disrupt global multi-view consistency. To address this challenge, we propose SceneExpander, which applies test-time adaptation to a parametric feed-forward 3D reconstruction model with two complementary distillation signals: anchor distillation stabilizes the captured scene using geometric cues from the captured views, while inserted-view self-distillation retains insertion-supported predictions to accommodate the misaligned view. Experiments on ETH scenes and online data demonstrate improved expansion behavior and reconstruction quality under misalignment.
Figures & tables
| Method | PSNR | SSIM | LPIPS | GPT-IS | GPT-RQ | H-IS | H-RQ |
|---|---|---|---|---|---|---|---|
| OminVGGT ( Peng et al. 2025 ) | 14.969 | 0.3647 | 0.370 | 3.16 | 2.66 | 2.26 | 2.40 |
| TTT3R ( Chen et al. 2025b ) | 13.483 | 0.2747 | 0.457 | 2.94 | 2.38 | 1.72 | 1.71 |
| WorldMirror ( Liu et al. 2025 ) | 19.295 | 0.614 | 0.357 | 3.50 | 2.61 | 4.04 | 4.07 |
| 3DGS ( Kerbl et al. 2023 ) | 14.046 | 0.3045 | 0.418 | 3.16 | 2.61 | 2.40 | 2.32 |
| SceneExpander (Ours) | 21.206 | 0.776 | 0.276 | 3.72 | 3.05 | 4.56 | 4.53 |
| Variant | PSNR | SSIM | LPIPS | GPT-IS | GPT-RQ |
|---|---|---|---|---|---|
| Baseline | 19.295 | 0.614 | 0.357 | 3.50 | 2.61 |
| + Anchor distill. | 20.763 | 0.714 | 0.329 | 3.52 | 2.96 |
| + Subset samp. & aug. | 20.892 | 0.720 | 0.322 | 3.56 | 3.24 |
| + Self-distill. ( ) | 21.124 | 0.757 | 0.294 | 3.70 | 3.08 |
| + Self-distill. ( ) | 20.856 | 0.704 | 0.318 | 3.84 | 2.88 |
| + Stoch. rest. (Full) | 21.206 | 0.776 | 0.276 | 3.72 | 3.05 |
Appendix figures & tables5 assets
Supplementary material from the paper’s appendix.