SceneFrom3D：基於幾何條件的戶外3D場景生成——透過視角調度與物件級控制

摘要

幾何條件化的3D場景生成技術能從使用者提供的幾何結構創建3D環境，直接控制場景結構與物體佈局。為生成此類3D場景，現有方法通常採用三階段設計：首先定義視圖排程，接著沿排定視角合成多視角觀測結果，最後從生成影像重建3D表徵。然而，對於室外場景而言，定義視圖排程成為主要瓶頸——大型、非結構化且無邊界的幾何結構使得難以獲得兼顧充分覆蓋率與穩定生成的視角。為解決此瓶頸，我們提出SceneFrom3D框架，該框架能自動從室外輸入幾何結構排定視圖。SceneFrom3D建構一個有向生成圖，其中節點代表錨定視圖，邊代表插值軌跡，藉此定義需合成的視圖、需內插的視角對，以及生成進行的順序。除自動視圖排程外，SceneFrom3D更透過物體級條件控制提升可控性：為每個物體分配用於外觀引導的識別影像，以及用於區域級幾何遵循參數。實驗證明，SceneFrom3D在幾何條件化室外3D場景生成中達到最先進水準，能產出高品質場景，同時具備可控物體外觀與幾何遵從性。

English

Geometry-conditioned 3D scene generation enables the creation of 3D environments from user-provided geometry, offering direct control over scene structure and object layout. To generate such 3D scenes, current methods commonly adopt a three-stage design that first defines a view schedule, then synthesizes multi-view observations along the scheduled views, and finally reconstructs a 3D representation from the generated images. However, defining the view schedule becomes a major bottleneck for outdoor scenes, where large, unstructured, and unbounded geometry makes it difficult to obtain views that provide sufficient coverage while supporting stable generation. To address this bottleneck, we present SceneFrom3D, a framework that automatically schedules views from outdoor input geometries. SceneFrom3D constructs a directed generation graph whose nodes represent anchor views and whose edges represent interpolation trajectories, defining which views to synthesize, which view pairs to interpolate, and in which order generation should proceed. Beyond automatic view scheduling, SceneFrom3D further improves controllability through object-level conditioning, assigning each object an identity image for appearance guidance and a geometry-adherence parameter for region-wise control over the input geometry. Experiments demonstrate that SceneFrom3D achieves state-of-the-art geometry-conditioned outdoor 3D scene generation, producing high-quality scenes with controllable object appearance and geometry adherence.