See the complete robot.
Then work on one part.
The assembly shows a chassis, four mounted wheels with shafts, four separate carriers, a removable deck, an upper housing and its roof. Select a component to understand where it fits, change its dimensions and save its own editable project.
Start here: open index.html. The original library of individual bodies and accessories remains available in parts.html. Both work from the extracted package; keep the assets folder beside the HTML pages.
Follow the wheel shaft into its carrier.
- Start with the assembled robot. Drag to rotate the scene and use the mouse wheel to zoom. The component tree lists the chassis, upper body and four wheel stations.
- Click a component in the tree or the 3D scene. Use Focus part to centre it or Isolate part to inspect it alone. A wheel carrier has a shaft bore and two chassis fixing holes.
- Click Inspect wheel attachment ↗. It selects the front-left carrier, separates the assembly partway and makes the housing transparent, and hides the roof so the wheel, shaft and carrier connection are easier to follow. Adjust Explode back to zero to see the assembled positions.
- Use X-ray housing or Hide roof to reveal the deck and upper body. Enable Part labels to identify the components while exploring.
- Change a selected component's dimensions, then return to the assembled view and check the resulting fit.
A shaft passes through a real hole.
Shaft diameter ≠ hole diameter
The shaft diameter is the measured metal component. The carrier aperture is the mating opening. For a round interface, diametral clearance = bore diameter − shaft diameter; radial clearance is half that value. A nominal 12.0 mm shaft and a 12.4 mm bore give 0.4 mm diametral clearance.
The example describes the CAD geometry. Printed hole size depends on the final material, orientation and process; verify a test coupon before printing four carriers.
The hole locates; torque restraint matters
A driven hub-motor axle also needs an anti-rotation interface. A round hole alone does not capture axle flats or react driving and braking torque. The model's generic axle/plate geometry explains the connection; replace it with the actual measured metal axle and torque plate detail before fabrication.
Shaft threads, cable exits, motor bearings, nuts and supplier-specific retention details must be matched to your real wheel unit. The bare-shaft floor-clearance check does not include the larger nut, washer or torque-plate envelope; those need their own clearance.
Each part has a job and a separate export.
| Component | What to customize | Interface to preserve |
|---|---|---|
| Chassis | Body family, length, width, height, wall and floor thickness. | Four carrier stations and the shared deck mounting pattern. |
| Wheel carriers | Carrier plate dimensions, thickness, shaft opening and axle drop. | Two side bolts per carrier; the shaft and aperture must remain concentric. |
| Wheels and shafts | Wheel diameter/width and the measured shaft dimensions. | Wheel clearance beside the carrier, shaft engagement through the bore and axle height. |
| Removable deck | Deck thickness and supported footprint. | Mounting holes remain aligned with the chassis pads. |
| Upper housing | Body enclosure dimensions and wall thickness. | Base attachment to the deck and the matching roof interface. |
| Roof / lid | Top thickness and mating clearances. | Housing outline, fastener pattern and service access. |
| Frame splice plates | Adjust the separate underside plate dimensions for the split-frame configuration. | The two plates align with the front/rear rail joint. Real fasteners and metal torque restraint are separate hardware requirements. |
Carrier and wheel changes affect the selected station. Use Apply these dimensions to all four carriers or the corresponding wheel button when they should match. Chassis dimensions and wheelbase are shared so the mated components follow the body; split-frame halves use linked chassis dimensions. A part project exported for separate editing is a snapshot, with no automatic link back to later assembly changes.
Read the same dimensions in the scene and part editor.
| Nominal setting | Default | How it is used |
|---|---|---|
| Chassis envelope | 300 × 180 × 55 mm | Length × width × height; wheels and carriers are outside this envelope. |
| Wheelbase | 200 mm | Axle stations at X = ±100 mm in the assembled robot. |
| Side bolt pair | 28 mm pitch · Ø5.4 mm | Two bores per station. The bolt line is halfway up the chassis wall. |
| Wheel carrier | 64 × 76 × 6 mm plate | Ribs and the annular boss bring overall thickness to 10 mm. Its wide face is flat for individual export. |
| Axle drop | 40 mm in this assembly | The shaft axis sits 40 mm below the chassis fixing-bolt line. Original inventory presets use 36 mm; the assembly exports its actual 40 mm setting. |
| Wheel hardware | Ø165 × 45 mm | Illustrative purchased wheel envelope; measure the actual motor/wheel. |
| Round shaft / bore | Ø12.0 / Ø12.4 mm | 0.4 mm diametral clearance in CAD. The axle opening is editable. |
| Deck / housing / roof | 6 / 70 / 4 mm | Deck thickness, housing height and roof thickness. Housing walls begin at 3 mm. |
| Roof mounting | 14 mm inset · Ø5.4 mm | Four roof bolts pass into the housing bosses. Inward nut pockets start at 8.4 mm across and 4.5 mm high. |
The assembly uses X forward, Y left and Z upward, with the ground at Z = 0. Individual printable-part exports return to their own flat Z = 0 datum. The original body guide uses that local datum, so its Z values are not ground heights.
Keep a complete assembly and a focused part project.
- Save the complete robot first. Use Save assembly to keep the complete editable robot as your master. Use Open project to restore an assembly file or a contextual part project saved by this assembly studio. A generic Part Studio file belongs in the separate Part Studio editor.
- Select the module you want to change. Work on that part while keeping the assembled view available for fit checks.
- Save the selected part as its own project. Use Save editable part project ↓ for a file or Open in Part Studio ↗ to continue in the individual-part editor. The file contains that part's nominal geometry in its local manufacturing orientation, not the exploded viewing position. Edits made in Part Studio are independent and do not automatically update the robot assembly.
- Export each printable component separately. Use the selected component's STL ↓ or OBJ ↓ export. STL carries geometry in millimetres; it does not retain editable parameters, colour or a material specification.
- Check one physical wheel interface first. Confirm the real shaft, carrier, torque restraint and bolts fit before printing the remaining body modules.
When two copies must differ: select their separate wheel/carrier entries to change each station, or save independent part projects for additional CAD features. Shared chassis dimensions deliberately keep the body interfaces aligned.
Measure the interfaces before increasing wall thickness.
A thicker body can still fail at a poorly restrained axle or a weak bolted joint. Start from wheel diameter and width, shaft shape and diameter, motor torque, total mass, battery dimensions and printer build volume. The assembly makes these relationships visible, while the build guide gives the original module datum and fastening layout.
Dimension checks
- Wheelbase is the front-to-rear axle spacing.
- Track is the distance between left and right wheel centres.
- Body width excludes carriers and wheels.
- Axle drop is measured below the carrier's chassis bolt line.
- Nominal ground clearance must include the lowest carrier, splice or fastener.
What this model establishes
It shows the nominal geometric assembly, real openings, part placement and editable modules. Mesh validity and geometric clearances do not establish payload capacity, fatigue life, water sealing or compatibility with an unidentified hub motor.
Use the printing and structure guide for orientation, fastening and prototype load checks. Retain the real wheel manufacturer's interface requirements.