Abstract:A common strategy to improve lidar segmentation results on rare semantic classes consists of pasting objects from one lidar scene into another. While this augments the quantity of instances seen at training time and varies their context, the instances fundamentally remain the same. In this work, we explore how to enhance instance diversity using a lidar object generator. We introduce a novel diffusion-based method to produce lidar point clouds of dataset objects, including reflectance, and with an extensive control of the generation via conditioning information. Our experiments on nuScenes show the quality of our object generations measured with new 3D metrics developed to suit lidar objects.