Techniques for improving flexural strength in 3D-printed object. The techniques generally include identifying a portion of a 3D model corresponding to the 3D-printed object to which one or more support posts should be added and adding support post descriptors to the 3D model within such a portion. The support post descriptor defines a position and at least one dimension of a support post cavity and a position and at least one dimension of a support post, both having a height corresponding to at least two layers of 3D-printable material. The model, including the support post descriptors are transmitted to a 3D printer to print the 3D model, which includes a support post cavity and a support post having a height of at least two layers.