### Information file for SAMPLEID_geom_struct.mat and SAMPLEID_vertices.txt files: ----------------------------------- 1) SAMPLEID_geom_struct.mat files: Version: MATLAB 7.9.0 (2009b) Contains geometric representation of detected particles: Vertices, Edges and normals are associated with faces. This is the same structure as used by qhull (ref. www.qhull.org) Matlab command for generating data structure: TCSet = repmat(struct('vertex', zeros(4,3,'double'), 'centroid', zeros(1,3,'double'), 'side', 70, 'border',0, ... 'face', repmat(struct('vertex',zeros(3,1,'uint8'),'edge',zeros(3,2),'normal',zeros(1,3,'double')),1,4)),Nparticles,1); TCSet = Nparticlesx1 struct array with fields: vertex centroid side border face = 1x4 struct array with fields: vertex edge normal Explanation: # Point coordinates [all in voxels, resolution 1 voxel = 100µm] T.vertex[4,3] double % vertices T.centroid[1,3] double % centroid of particle # Faces: T.face[4].vertex[3(index_into_vertex)] uint8 % vertices T.face[4].edge[6,2(index_into_vertex)] uint8 % edges, NB: left hand ordering T.face[4].normal[1,3] double % normals # Scalar values: T.side double % Sidelength [voxels] T.border % if particle belongs to boundary of volume(=1) or core region(=0) ----------------------------------- 2) SAMPLEID_vertices.txt files: These files contain the complete information of all particles in each packing. The header gives additional sample specific information: - SampleID discloses the preparation method as outlined in our paper. (LOOSE, TAP, RAMP, VIB). - Packing fraction as determined in the core region (with bounding cylinder). - Contact number as determined from the sidelength scaling curve (see supplements) All vertices are given in voxel units, resolution: 1 voxel=100 µm Each row is composed of the xyz coordinates of the 4 vertices: Vertex1 Vertex2 Vertex3 Vertex4 (that is:) x1 y1 z1 x2 y2 z2 x3 y3 z3 x4 y4 z4 Boundary[yes=1/no=0] Firstly, the particles in the core region are listed (boundary=0), which determine the packing fraction and the contact number. Secondly, the boundary particles are listed (Boundary=1). Note that for correct computation of contact numbers in the core region, boundary particles are necessary as possible neighbors of core particles.