  We present iSeg, a new interactive technique for segmenting 3D shapes.
Previous works have focused mainly on leveraging pre-trained 2D foundation
models for 3D segmentation based on text. However, text may be insufficient for
accurately describing fine-grained spatial segmentations. Moreover, achieving a
consistent 3D segmentation using a 2D model is challenging since occluded areas
of the same semantic region may not be visible together from any 2D view. Thus,
we design a segmentation method conditioned on fine user clicks, which operates
entirely in 3D. Our system accepts user clicks directly on the shape's surface,
indicating the inclusion or exclusion of regions from the desired shape
partition. To accommodate various click settings, we propose a novel
interactive attention module capable of processing different numbers and types
of clicks, enabling the training of a single unified interactive segmentation
model. We apply iSeg to a myriad of shapes from different domains,
demonstrating its versatility and faithfulness to the user's specifications.
Our project page is at https://threedle.github.io/iSeg/.
