  This paper introduces a 3D shape completion approach using a 3D latent
diffusion model optimized for completing shapes, represented as Truncated
Signed Distance Functions (TSDFs), from partial 3D scans. Our method combines
image-based conditioning through cross-attention and spatial conditioning
through the integration of 3D features from captured partial scans. This dual
guidance enables high-fidelity, realistic shape completions at superior
resolutions. At the core of our approach is the compression of 3D data into a
low-dimensional latent space using an auto-encoder inspired by 2D latent
diffusion models. This compression facilitates the processing of
higher-resolution shapes and allows us to apply our model across multiple
object classes, a significant improvement over other existing diffusion-based
shape completion methods, which often require a separate diffusion model for
each class. We validated our approach against two common benchmarks in the
field of shape completion, demonstrating competitive performance in terms of
accuracy and realism and performing on par with state-of-the-art methods
despite operating at a higher resolution with a single model for all object
classes. We present a comprehensive evaluation of our model, showcasing its
efficacy in handling diverse shape completion challenges, even on unseen object
classes. The code will be released upon acceptance.
