Do 3D Large Language Models Really Understand 3D Spatial Relationships? - Ma, Xianzheng; Sun, Tao; Chen, Shuai; Bhalgat, Yash; Gu, Jindong; Chang, Angel; Armeni, Iro; Laina, Iro; Peng, Songyou; Prisacariu, Victor (International Conference on Learning Representations, 2026)