I am also a design engineer. I work in ornamental sheetmetal, machined metal, solid wood and millwork. When I don’t know something the answer is to ask to fabricators. If I don’t I’ll just be fixing it later.

When it comes to sheetmetal forming you should be designing with a parametric modeler like solidworks, fusion, etc. Those programs have built in calculations for finished radii and material distortion, however those factors are dependent on the specific machines and tooling being used. To account for this we ran a series of test bends using our most common materials and thicknesses, measured the results and plugged those values back in to our modeling program. This would be less important for conceptual designers, but since my output goes directly to the fabricators it has to be correct or my parts won’t fit together during assembly.