#### Abstract

Pipes are the basic building block in many industrial sites like electricity and chemical plants. Although
pipes are merely cylindrical primitives which can be defined by axis and radius, they often consist of
additional components like flanges, valves, elbows, tees, etc. 3D pipes are typically dense, consisting of a
wide range of topologies and geometries, with large self-occlusions. Thus, reconstruction of a coherent 3D pipe
models from large-scale point clouds is a challenging problem. In this work we take a prior-based
reconstruction approach which reduces the complexity of the general pipe reconstruction problem into a
combination of part detection and model fitting problems. We utilize convolutional network to learn point cloud
features and classify points into various classes, then apply robust clustering and graph-based aggregation
techniques to compute a coherent pipe model. Our method shows promising results on pipe models with varying
complexity and density both in synthetic and real cases.

Keywords: Point cloud, Pipes reconstruction, Convo-
lution network, Skeleton extraction