Recorded design and revision workflow
The original brief, actual app follow-ups, connected CAD work and engineering review are recorded as separate steps so that a reader can follow the workflow and inspect its limits.
Recorded prompts and subsequent work
1. Original short brief
METHEUS app — GPT-5.6 Luna / medium / Basic
2026-09-20T23:02:09.500352+09:00
Start in a new conversation and an empty CAD document. The successful search returned 300 kinematic candidates after retries. This brief did not independently produce the final assembly.
2. Recorded candidate-recovery follow-up
METHEUS app — GPT-5.6 Luna / medium / Basic
2026-09-20T23:19:26.496322+09:00
The first CAD concept did not preserve the returned mechanism geometry. This follow-up requested original exports for comparison rather than accepting substituted links.
3. Recorded passive-slider export follow-up
METHEUS app — GPT-5.6 Luna / medium / Basic
2026-09-20T23:25:04.232248+09:00
An export-only request recovered the passive-slider candidate. The connected authoring session subsequently recovered the exact native skeletons through METHEUS and FreeCAD.
4. Recover the source, compare candidates, and develop the assembly
Connected authoring session — GPT-6 Astra / Ultra, using METHEUS and FreeCAD
21 September 2026 (KST)
The authoring session passed the exact exports through the METHEUS/FreeCAD connection, compared three original 72-pose mechanisms, selected four-bar index 93 / rank 94, and performed the later detailed CAD and analysis work documented for v1.2. This work was separate from the 54-word initial input and the app-side export requests.
5. Revision request: longer fingers and a UR5e interface
METHEUS app — GPT-5.6 Luna / medium / Basic
2026-09-21T10:45:19.757000+09:00
Continue with the selected four-bar in the current CAD document. The requested 25 to 50 mm dimension is exposed reach beyond the front cover. Initial app edits were reviewed for local motion frames, mating flange geometry, and BOM accuracy before any final design claim.
6. Additional request after review
METHEUS app — GPT-5.6 Luna / medium / Basic
2026-09-21T10:53:27.137000+09:00
Continue in the same conversation after engineering review. This request separates finger bending from planar drive torque and asks for an actual mating flange and a recalculated BOM. An idle app response does not establish that the final geometry or loads have been validated.
7. Review and verify the revised geometry and loads
Connected review session — GPT-6 Astra / Ultra, using METHEUS API and FreeCAD
21 September 2026 (KST)
Following both app responses, connected engineering corrections restored the original finger motion frames and created the actual UR5e mating hardware. The reviewed gripper has 50 mm exposed fingers and no robot reference. Review covered the preserved 72-pose source, finite CAD clearance, part-derived BOM, six new individual-finger FEM cases, and a separate 72-pose quasistatic planar-drive calculation. The two app responses alone were not treated as a completed validated design.
Reviewed outcome
The final revision has 97 physical parts, 36 BOM groups and a 1.032 kg mass estimate. The original generated source data are preserved. The documented 72-pose clearance review found no unintended interference within its defined scope.
Actual extended-finger FEM covers both fingers at three mesh sizes. Displacement is stable for the fixed-foot idealization, while sharp-corner peak stress is not converged. A separate planar virtual-work calculation reports drive demand. Physical payload retention and full-assembly validation remain open.
Reproducibility and intermediate errors
The 54-word initial brief, two historical recovery requests, the 36-word revision, and the 127-word review request are preserved verbatim. Model updates, conversation state, search results, and engineering decisions can change the geometry and ranking. For a new Generate run, use its actual job identifier and selected candidate indices instead of blindly reusing the historical IDs below.
Initial app CAD handoff and revision geometry required review and corrections. The source exports, original motion frames, exposed-reach datum, mating interface and model-derived BOM were explicitly checked. App prompt completion alone was not accepted as final geometry or structural validation.