Same product. Materials own the numbers. Density, stiffness, conductivity, process allowables. CAD picks a VariantId. It does not own E, k, or mu. You are not buying a materials database to sit next to CAD. You are replacing the stack.
The same variant is what CAM cuts, CAE solves, and ERP buys. One library. One identity. A coupon is a new variant in MAT, then you select it. There is no override box on the CAD part for constitutive values. Appearance is CAD. Emissivity is a material surface state. Those are not the same field.
Missing density means mass is unknown. We do not fake a number to close a BOM. Filament, powder, and resin are material variants, not a color swatch. Sheet-metal K-factor is a process number on the tool pair. The variant still supplies E and yield if we compute springback.
This is one of twelve products you stop buying. A licensed materials library, a spreadsheet of alloys, a CAD color called 6061: those are the vendors and habits this page exists to retire. One Windows executable. n23d-2026.
What we will not fake. We write 100% Rust. We do not wrap a vendor materials database and call it ours. File readers are interchange. This page is the contract. The numbers live here or they do not live.
If CAD still owns density, we failed. MAT is the library. Everyone else selects.
