Ferroelectric domain walls are a paradigmatic example for the rich physics and application opportunities of topological defects and attract continuously growing interest. Being embedded in a 3D material, however, the domain walls are not perfectly flat and can form networks with so far largely unknown consequences for the emergent electronic transport phenomena. In my talk, I will discuss a new tomography approach that facilitates measurements of both the 3D structure of domain walls and their conductance in one experiment and with nanoscale spatial resolution. The results show that curvature effects allow for multi-level resistance control and complex electronic responses based on individual domain walls, expanding the field of domain wall electronics into the realm of nanoscale synaptic devices and unconventional computing.