ORIGEN: Zero-Shot 3D Orientation Grounding in Text-to-Image Generation
Authors: name: Yunhong Min, name: Daehyeon Choi, name: Kyeongmin Yeo, name: Jihyun Lee, name: Minhyuk Sung

We introduce ORIGEN, the first zero-shot method for 3D orientation grounding
in text-to-image generation across multiple objects and diverse categories.
While previous work on spatial grounding in image generation has mainly focused
on 2D positioning, it lacks control over 3D orientation. To address this, we
propose a reward-guided sampling approach using a pretrained discriminative
model for 3D orientation estimation and a one-step text-to-image generative
flow model. While gradient-ascent-based optimization is a natural choice for
reward-based guidance, it struggles to maintain image realism. Instead, we
adopt a sampling-based approach using Langevin dynamics, which extends gradient
ascent by simply injecting random noise--requiring just a single additional
line of code. Additionally, we introduce adaptive time rescaling based on the
reward function to accelerate convergence. Our experiments show that ORIGEN
outperforms both training-based and test-time guidance methods across
quantitative metrics and user studies.