2026 Singh CADEngBench Engineering CAD

A CAD model is not engineering-grade merely because it looks correct. It must satisfy design requirements, respond predictably to parameter changes, support controlled edits, match a reference structural response under a declared analysis, and connect to other parts through valid joints. We present CADENgBENCH, a two-track benchmark for these capabilities. CADENgBENCH evaluates 300 parametric parts, each used for one zero-to-CAD task and one functional-editing task (600 tasks in total), through boundary-representation (B-Rep) validity, engineering and DFM checks, parameter-family perturbations, functional editing, and matched linear-static FEA in CalculiX. CADENgBENCH-A evaluates 150 body pairs through ranked joint retrieval, exact face-and-edge grounding, joint-frame prediction, and kinematic verification. Evaluating parts with multimodal, code-capable models, editing supplied CAD is substantially easier than generating it, while complex edits and match FEA remain difficult. Assembly predictions often look to the relevant region but fail to recover the recorded joint or mating entities. These results show that CAD evaluation cannot just engineer behavior rather than appearance alone.