PIG model

This repository contains key files and description of the PIG model proposed in the paper Three-dimensional surface motion capture of multiple freely moving pigs using MAMMAL (not available yet). It is a part of MAMMAL project. It is a SMPL/SMAL-like skinning model yet without shape-blend-shape or pose-blend-shape. However, it still provides the first skinning model for pigs, which is an important complement for existing shape models. This model is built upon the observations of Guangxi Bama mini-pig, which is widely used for disease modeling.

TODO

• Provide .fbx file.

Contents

core_txt_files folder

This folder contains txt files which are the core of the PIG model.

vertices.txt: 11239 * 3 float matrix, T-pose (or rest pose) position of all the vertices.

t_pose_joints.txt: 62 * 3 float matrix, T-pose (or rest pose) position of 62 embeded joints. The joint order, topology and names are shown in the figures.

skinning_weights.txt: 38841 rows. Each row has three number: j v w. j is the index of joint. v is the index of vertex, w is a float value representing the skinning weight connecting joint j and vertex v. Actually, the full skinning weights can be represented as a 62 * 11239 matrix, whose non-zero values are list in the 38841 number pairs.

J_regressor.txt: 8079 rows, same structure to skinning_weights.txt. Differently, J_regressor is used to obtain joint positions given vertices, which is useful when we need to obtain the updated t-pose joints after deforming the t-pose vertices.

parents.txt: 62 integer number indicating the joint tree topology. The i-th number indicates the parent joint id of i-th joint. If -1, means it is the root joint.

textures.txt: 12208 * 2 float matrix. It is the texture coordinates. It is more than vertex number because some vertices correspond to two tex coordinates. They are mapped thourgh surface triangle faces.

faces_vert.txt: 22446 * 3 integer matrix. Means the surface triangles. Each number is vertex index (start from 0).

faces_tex.txt: 22446 * 3 integer matrix. Also the surface triangles, yet each number is texture index (start from 0). The face order is the same to faces_vert.txt.

full_txt_files folder

This folder contains several additional files showing some other useful features of the PIG model. It also contains two .obj files showing the PIG model (PIG.obj) and a coarse PIG model (PIG_reduced.obj). These .obj files can be opened with MeshLab, Maya, Blender or other graphics softwares.

body_parts.txt: 11239 integer numbers indicating which high-level body part a vertex belongs to. The body part order is defined in body_part_defs.txt. We defined 12 body parts, indexed from 1, so we set the 0 body part with name NOT_BODY.

reduced_ids.txt: 546 integer numbers mapping the full 11239 vertices to a coarse mesh vertices. This coarse PIG model is useful for accelerating distance computing between two posed meshes.

reduced_faces.txt: 1088 * 3 integer matrix. Faces for the coarse PIG model.

sym.txt: 11239 integer numbers. The i-th number indicate that vertex index which is symmetric to i-th vertex with respect to the x-axis.

pkl_files folder

PIG_core.pkl contains the dict of PIG parameters same to core_txt_files.

PIG_full.pkl contains the dict of PIG parameters same to full_txt_files.

Dependencies

To run the code here, the following packages should be installed: numpy, scipy.

Citation

If you use this code in your research, please cite the paper

@article{MAMMAL, 
    author = {An, Liang and Ren, Jilong and Yu, Tao and Hai, Tang and Jia, Yichang and Liu, Yebin},
    title = {Three-dimensional surface motion capture of multiple freely moving pigs using MAMMAL},
    booktitle = {},
    month = {July},
    year = {2022}
}