3xD 1.2-rc3 release notes
10 November 2026 · Release candidate · Pending physical validation and approval
This page compares the previous complete release, 1.0-rc2, with the new complete release, 1.2-rc3. It covers all changes accumulated between those downloadable kits, including the intervening rail update and chassis revisions.
Changes since the previous complete release
| Area | 1.0-rc2 | 1.2-rc3 |
|---|---|---|
| Battery-area cutouts | Two angular windows. | One 84 mm-wide 3xD logo cutout, centred beneath the battery at its neutral position and readable from underneath. Two 4 mm bridges hold the centre of the D. |
| Front shoulder cutouts | Two angular openings. | Four swept blade slots. |
| Small rear cutouts | Two swept openings. | Four chevron slots in the same rear areas. The large motor opening is retained. |
| Lower spring pockets | 5.7 mm floor diameter, 6.8 mm mouth and 10.8 mm shoulder. | 10.7 mm floor diameter, 11.8 mm mouth and 15.8 mm shoulder: each widened by 5 mm. Depth, seating height and fixing positions are retained. |
| Parts to replace | Earlier chassis and side rails. | One chassis plate and both side rails. The other 42 STL selections retain their exact earlier geometry. |
The comparison was checked against both frozen release manifests and file hashes, separately for GRP and printed setups. Each still contains 45 distinct STL selections and 46 required instances; no part types were added or removed. Both complete kits include the accumulated changes, so older update packs do not need to be combined manually.
Download the complete kits
- Download 1.2-rc3 — complete 3 mm GRP kit (ZIP, 4.2 MB)
- Download 1.2-rc3 — complete 4 mm printed chassis kit (ZIP, 4.2 MB)
Each pack includes 45 distinct STL files: required parts plus optional matched arms, braces and shims. The parts list specifies 46 required instances for one car, including the two fit-pending bearing inserts. Hardware notes, cutting DXFs, validation records and file checksums are included. Optional alternatives are not all fitted together.
These are complete part inventories. You do not need to combine older packs manually. STLs are unsliced parts; no G-code is included.
Logo detail
The final logo has 4 mm supports for the centre of the D. Its underside reading direction, centred battery position and support width are all included in the complete-release comparison above.
Updating from the previous release
From 1.0-rc2: replace the chassis and both side rails. Mounting interfaces, chassis thicknesses, the motor aperture and the remaining 42 STL selections are retained. Use the complete pack matching your GRP or printed chassis to preserve its bumper and bearing geometry.
If you already fitted intermediate updates: 1.1-rc1 introduced the wider rails, so those rails can be reused. The 1.2-rc1 and 1.2-rc2 chassis were intermediate versions of this cutout design. From 1.2-rc2, only the chassis changes: D bridges increase from 3 mm to 4 mm. That is the final revision within this release, rather than the full set of changes since the previous complete kit.
Validation and remaining checks
Both chassis exports are single connected watertight solids. Cross-sections confirm two 4 mm D bridges, correct 3 mm and 4 mm plate thicknesses, and preservation outside the bridge region relative to rc2. Pack manifests, quantities, ZIP integrity and file hashes were checked. The original A1 retainer, selected P2 cups and setup-specific bearing selections are preserved.
Physical spring seating, bearing fit, support, plate stiffness, fatigue and full steering/suspension movement still need checking. CAD checks do not establish competition compliance or measured speed gains. This remains a release candidate; no print job was sent.
Previous complete release: 1.0-rc2 · Intermediate revision: 1.2-rc2 · Wider spring-pocket rails: 1.1-rc1 · All release notes