Confused about the meaning of Vertex IDs and Facet IDs

[HolaYan]

Hi,
Thanks for your great work! I'm confused about Vertex IDs and Facet IDs in interaction_contact_signature.json of FlickrCI3D_signature stand for what. Could you please give some more details about them? Thanks in advance!!!

[mihaifieraru]

Hi,

The interaction contact signatures are annotated contact correspondences between the body surfaces of the two people. Each correspondence is set between two GHUM template surfaces. The annotators click on the surfaces, and we gather the triangle / facet IDs that are selected. We also compute the closest GHUM vertex ID to the click. These give us the GHUM Facet IDs and Vertex IDs contact correspondences, respectively. We also register the SMPLX model to the GHUM template and transfer these annotations to the Facet and Vertex IDs of the SMPLX model.

One way to use these correspondences is to gather the 3d positions for the corresponding Vertex IDs of two predicted meshes and constrain their distance to be 0, as they should be in contact. Please take a look at our paper https://ci3d.imar.ro/sites/default/files/public/pdf/Fieraru_2020_CVPR.pdf for other losses ideas.

Best,
Mihai