We present PointInfinity, an efficient family of point cloud diffusion
models. Our core idea is to use a transformer-based architecture with a
fixed-size, resolution-invariant latent representation. This enables efficient
training with low-resolution point clouds, while allowing high-resolution point
clouds to be generated during inference. More importantly, we show that scaling
the test-time resolution beyond the training resolution improves the fidelity
of generated point clouds and surfaces. We analyze this phenomenon and draw a
link to classifier-free guidance commonly used in diffusion models,
demonstrating that both allow trading off fidelity and variability during
inference. Experiments on CO3D show that PointInfinity can efficiently generate
high-resolution point clouds (up to 131k points, 31 times more than Point-E)
with state-of-the-art quality.

PointInfinity 是一种高效的点云扩散模型，使用基于 transformer 的架构和固定大小的分辨率不变的潜在表示，可以在训练过程中使用低分辨率点云实现高效训练，同时在推理过程中生成高分辨率的点云。实验表明，PointInfinity 可以以最先进的质量高效生成高分辨率的点云。

PointInfinity: 分辨率不变的点扩散模型

PointInfinity: Resolution-Invariant Point Diffusion Models

3D building generation with low data acquisition costs, such as single
image-to-3D, becomes increasingly important. However, most of the existing
single image-to-3D building creation works are restricted to those images with
specific viewing angles, hence they are difficult to scale to general-view
images that commonly appear in practical cases. To fill this gap, we propose a
novel 3D building shape generation method exploiting point cloud diffusion
models with image conditioning schemes, which demonstrates flexibility to the
input images. By cooperating two conditional diffusion models and introducing a
regularization strategy during denoising process, our method is able to
synthesize building roofs while maintaining the overall structures. We validate
our framework on two newly built datasets and extensive experiments show that
our method outperforms previous works in terms of building generation quality.

利用图片条件模型扩散点云模型的新型三维建筑生成方法，在保持整体结构同时综合生成建筑顶部结构，实验证明该方法在建筑生成质量方面优于之前的研究。