  Modeling the interaction between humans and objects has been an emerging
research direction in recent years. Capturing human-object interaction is
however a very challenging task due to heavy occlusion and complex dynamics,
which requires understanding not only 3D human pose, and object pose but also
the interaction between them. Reconstruction of 3D humans and objects has been
two separate research fields in computer vision for a long time. We hence
proposed the first RHOBIN challenge: reconstruction of human-object
interactions in conjunction with the RHOBIN workshop. It was aimed at bringing
the research communities of human and object reconstruction as well as
interaction modeling together to discuss techniques and exchange ideas. Our
challenge consists of three tracks of 3D reconstruction from monocular RGB
images with a focus on dealing with challenging interaction scenarios. Our
challenge attracted more than 100 participants with more than 300 submissions,
indicating the broad interest in the research communities. This paper describes
the settings of our challenge and discusses the winning methods of each track
in more detail. We observe that the human reconstruction task is becoming
mature even under heavy occlusion settings while object pose estimation and
joint reconstruction remain challenging tasks. With the growing interest in
interaction modeling, we hope this report can provide useful insights and
foster future research in this direction. Our workshop website can be found at
\href{https://rhobin-challenge.github.io/}{https://rhobin-challenge.github.io/}.
