Our SDC2 3D CNN backbone architecture. The left column provides layer structural properties, whereas the right column indicates the spatial output dimension starting from a 64 × 64 × 256 input cube. Layers are stacked top to bottom. The layer width scales with the number of filters. Layer colors encode the stride setting: green preserves dimensions, orange reduces the frequency dimension by two, red reduces all dimensions by two, and blue reduces sky dimensions by two. The output grid size and the predicted parameters are shown next to the last layer.