We design modular and rotationally equivariant DeepSets for predicting a continuous background quantity from a set of known foreground particles. Using this architecture, we address a crucial problem in Cosmology: modelling the continuous electron pressure field inside massive structures known as “clusters.” Given a simulation of pressureless, dark matter particles, our networks can directly and accurately predict the background electron pressure field. The modular design of our architecture makes it possible to physically interpret the individual components. Our most powerful deterministic model improves by 70% on the benchmark. A conditional-VAE extension yields further improvement by 7%, being limited by our small training set however. We envision use cases beyond theoretical cosmology, for example in soft condensed matter physics, or meteorology and climate science.