## 1 Introduction
The model predicted warpage better for the square pipes than the circular with a maximum percent difference overall of 25% [52]. [PERSON] et al. [53; 54; 55; 56; 57] examined the effects of various printing parameters using a SC-TMA model built in COMSOL that included gravity effects. Short rectangular prisms made of polypropylene were represented using a thermo-viscoelastic material model that included crystallization [53; 54; 55; 56; 57]. While [PERSON] et al. [53; 54; 55; 56; 57] state that contact between the bed and part was modeled using a spring foundation, no details of the implementation are provided and their cited source has a fixed then released boundary condition [58]. The warpage at one or two points per specimen is compared to experiments and agrees very well with measured values [53; 54; 55; 56; 57]. FEA-based SC-TMA is not the only method being used to model FDM. [PERSON] and [PERSON] [59] presented a fully coupled thermo-mechanical model of a two-dimensional wall. Unlike in a sequentially coupled analysis where the thermal problem is independent and can be solved before the structural problem, in a fully coupled analysis, both responses are dependent on the other and the two problems must be solved simultaneously [59]. They compared their results to those from a SC-TMA and found very small differences in final displacement [59]. [PERSON] et al. [60] devised a framework to model deposition from the nozzle and liquid, transition and solid phases of the polymer during FDM. They used the Arbitrary Lagrangian-Eulerian method to solve their coupled governing equations [60]. They applied the method to a hypothetical polystyrene wall one bead thick and four beads tall in plane strain conditions [60]. [PERSON] et al. [61] applied the one fluid formulation to fully modelling FDM which is a finite volume, front tracking method with two meshes, one stationary and one moving. They used the method to examine the effects of overhang using an inverted cone, spacing between two adjacent filaments using a two-bead-wide by two-bead-high wall and bridging by printing a single filament connecting two spaced out single bead walls four beads high [61]. Though these methods have the potential to more accurately capture the physics of FDM, their complexity and computational demand are quite high. None of these methods were compared against experimental data and the one that was compared to a SC-TMA found only small differences in displacements. Furthermore, these models consist of novel code that would be difficult to implement for wider classes of simulations and for the reduction in trial and error during large-format FDM. While the discussion above shows there has been much work on simulating small-scale 3D printing, the simulation of large-scale 3D printing poses other challenges. Radiative heat transfer is a significant mode of heat transfer, unlike in small-scale printing [62]. Also, be cause of the reduced surface area to volume ratio, large-scale parts cool much more slowly and can therefore be more prone to sagging [62]. While most findings from small-scale SC-TMA are most likely applicable to large-scale SC-TMA in a general sense, it is still very important to have models specifically designed for use at large scale. [PERSON] et al. [63] created a structural simulation including element activation of the printing of a car made of short carbon ABS. Material properties were determined using a multi-scale homogenization approach that included damage, and stresses in each layer were calculated using CLT [63]. Measured temperatures were input into the structural model [63]. Locations of high stress in the model qualitatively matched where the printed structure cracked [63]. [PERSON] et al. [64] performed a SC-TMA on the printing of a 122 cm long by 38.1 cm tall single bead wall made of carbon fiber ABS. The wall was printed on an aluminum bar that allowed for deflection measurements and the material properties of the wall were temperature dependent and determined through experiments and multiscale modeling [64].