Computational modeling of superconducting magnets allows for predicting and understanding magnet behavior. The commercial software ANSYS is a widely used finite element software for mechanical, thermal, and electromagnetic modeling of superconducting magnets. ANSYS also allows its user to create custom elements by programming the elements’ properties and its finite element matrices. These user elements can capture additional material properties and physics that current ANSYS elements do not. Once compiled, they are then compatible with all other aspects of the software, including geometry generation, meshing, solving, and post-processing. Additionally, these elements can also be used with the multiphysics solver. We have developed two 3D user elements, one thermal and one electromagnetic with circuit coupling. In addition to the basic capabilities of ANSYS, they capture quench propagation, interfilament coupling currents, current sharing, and temperature and field dependent material properties. Two-dimensional user elements have previously been developed; however, modeling superconducting magnets in 3D allows for better representation of end effects, and other non-symmetric physics. Using the ANSYS multi-field solver, these two elements are shown to simulate coupled transient electromagnetic, thermal, and circuit effects for Nb3Sn undulators and other magnets built and tested at Lawrence Berkeley National Laboratory, particularly within the MDP. The effects of quench, interfilament coupling currents, and structural eddy currents are studied and compared to magnet test data while steps towards parallelization are also explored.