To generate realistic models of paper structures, the simulation of binder addition during paper manufacturing is essential. In PaperGeo, the process Add Binder reproduces the coating and bonding with binder of paper fibers, filler, and other components, often done to improve structural integrity, water retention, or finish to the paper sheet.

Adding binder to a structure means adding material in the shape of a concave meniscus in the pore space where surfaces in that structure’s material get close together. If there is no pore material in the structure, a warning is given.

For hollow objects, such as cellulose fibers, curved cellulose fibers, hollow fibers, curved hollow fibers, and hollow spheres, the algorithm under Add Binder needs analytic data (GAD objects) to discern that the empty voxels inside the fibers are not part of the pore space. Without analytic data, i.e., when using voxelized models, binder is also added inside the hollow fibers, which is physically inaccurate.