Primvaria

Primvaria · Quincaillerie

Limits and roadmap

Everything Quincaillerie does not do or has not verified, stated plainly, and what comes next.

Limits

  • Nominal, not measured. Fastener dimensions come from public tables, not from the standards; cell masses and spring forces are typical. Screws are fully threaded (no plain shank) and have no chamfer under the head.
  • Plausible variation, not measured distributions. The ranges (fits, defect sizes, wear, spring scatter) are realistic orders of magnitude, not statistics of a production line. Dents and corrosion crusts are visual only; crushed threads, bends, burrs, oval nuts and dished washers change the collision too.
  • Collision in pieces. A thread is ≈ 1000 convex pieces: exact enough to screw, heavy for large scenes (a scene of 100 screws is 100 000 shapes). Engines that size their contact buffers in advance feel it first: loaded in Newton (CPU), a scene of 3 M8 screws, nuts and washers (4 224 shapes) filled its default buffer of 210 600 contacts and the washers fell through the floor; with 400 000 they rest, the buffer still full. Raise the engine's contact limits for threaded parts, keep them few per scene, or generate the parts that only need to fall, pile up and be grasped with --collider simple.
  • Simple colliders do not screw or jam. With --collider simple a nut slides freely over a shank and a crushed thread no longer stops it: the defect is still drawn, recorded and visible, but it is not physical. Bent shanks, oval nuts and dished washers keep their effect.
  • Simplified holders. Generic designs (ABS boxes, a flat spring plate), not a product; no electrical contact model.
  • Blender springs start at rest. See Blender: a cell placed already seated is not pressed by the spring.
  • Isaac Sim not tested here. The files follow the standard UsdPhysics schemas, with the PhysX settings in a layer over each file, but have not been loaded in Isaac Sim (no NVIDIA GPU); drive units and contact offsets may need adjusting there.

Roadmap

  1. Tools that go with the parts: screwdriver bits and screwdrivers, hex keys and wrenches matched to the drives (--with tool), and tapped bases.
  2. More fasteners: socket head cap screws (ISO 4762), countersunk and pan head screws, partially threaded shanks, lock and spring washers.
  3. A PhysX test in Isaac Sim; CAD export (STEP) of the same parametric parts.
  4. Assembly tasks: torque, misalignment tolerances, success labels.