3D cheap, lightweight and robust cellulosic parts can be obtained via extrusion of a cellulosic aqueous paste followed by air-drying. During the air-drying step, an anisotropic shrinkage occurs. The objective of this study is to characterize the macro and mesoscale phenomena occurring during the drying process. We used sub-minute laboratory X-ray microtomography during air-drying tests combined with advanced image analysis including Digital Volume Correlation to reveal the mechanisms that took place at the sample and at the filament scales. This allowed the qualitative and quantitative analysis of the structural and kinematical changes occurring during the air-drying. The macroscopic anisotropic shrinkage of the structure is associated with a decrease of the solid fraction of the cube and a decrease of the volume of the central pore, a decrease of the number and of the volume of the inter-filament and intra-filament pores, a change of the shape and dimensions of the filaments cross section. We observed delamination effects, increase of the number of inter and intra filament pores. These results complete the analysis commonly carried out at the macroscale and are necessary to build a model for the prediction of drying mechanisms of 3D printed part of cellulose and to propose more accurate compensation strategies.