Vision Language Models (VLMs) have achieved impressive performance in 2D image understanding; however, they still struggle with spatial understanding, which is fundamental to embodied AI. In this paper, we propose SpatialBot, a model designed to enhance spatial understanding by utilizing both RGB and depth images. To train VLMs for depth perception, we introduce the SpatialQA and SpatialQA$\boldsymbol{E}$datasets, which include multi-level depth-related questions spanning various scenarios and embodiment tasks. SpatialBench is also developed to comprehensively evaluate VLMs' spatial understanding capabilities across different levels. Extensive experiments on our spatial-understanding benchmark, general VLM benchmarks, and embodied AI tasks demonstrate the remarkable improvements offered by SpatialBot. The model, code, and datasets are available at https://github.com/BAAI-DCAI/SpatialBot.

Synthetic training data has gained prominence in numerous learning tasks and scenarios, offering advantages such as dataset augmentation, generalization evaluation, and privacy preservation. Despite these benefits, the efficiency of synthetic data generated by current methodologies remains inferior when training advanced deep models exclusively, limiting its practical utility. To address this challenge, we analyze the principles underlying training data synthesis for supervised learning and elucidate a principled theoretical framework from the distribution-matching perspective that explicates the mechanisms governing synthesis efficacy. Through extensive experiments, we demonstrate the effectiveness of our synthetic data across diverse image classification tasks, both as a replacement for and augmentation to real datasets, while also benefits such as out-of-distribution generalization, privacy preservation, and scalability. Specifically, we achieve 70.9% top1 classification accuracy on ImageNet1K when training solely with synthetic data equivalent to 1 × the original real data size, which increases to 76.0% when scaling up to 10 × synthetic data.