How CAD Fits Into Product Development

In modern physical product development, the 3D CAD model is the authoritative master document. It dictates every downstream operation: finite element analysis (FEA), tooling design, CNC machine toolpaths, injection mold flow simulation, assembly instructions, and packaging dielines.

If the CAD contains errors—such as non-uniform walls, inverted surface normals, or microscopic interferences—those errors multiply into thousands of dollars of scrapped tooling downstream.

A common mistake among non-technical founders is confusing 3D animation meshes (STL, OBJ, FBX) with engineering CAD solids (STEP, SLDPRT).

Animation meshes consist of flat triangular facets. While suitable for video games or basic desktop 3D printing, they have no mathematical concept of a true circle or cylinder. Engineering CAD utilizes Boundary Representation (B-Rep) and Non-Uniform Rational B-Splines (NURBS), defining curves through exact calculus equations capable of sub-micron precision.

When handing off digital geometry to factories, neutral file formats are crucial:

• STEP (ISO 10303): The undisputed global standard. Protocols AP214 and AP242 carry solid geometry, color layers, and embedded GD&T annotations.

• Parasolid (.X_T): The underlying geometric modeling kernel for SolidWorks, NX, and Onshape. Ideal for zero-translation loss between Siemens-kernel CAD packages.

• IGES: An older surface standard from 1980. Still useful for legacy tooling shops but prone to stitched surface gaps.

Professional CAD modeling is organized hierarchically. By establishing a master skeleton sketch, modifications to primary dimensions (such as battery height or wall thickness) cascade automatically through all dependent parts without breaking the assembly.

Before LOOP hands off CAD, models undergo rigorous verification: draft angle analysis (ensuring parts can release from mold cores), undercut identification, parting line placement, and thickness uniformity verification.