The problem
On an electric motorcycle the tank space holds battery or electronics, and the fairing must cool the battery and controller while protecting the rider. Fairings are large visible panels where every wobble shows in reflections. Students need to learn to break a form into producible panels with shut lines, manage continuity across boundaries and keep the battery package and airflow openings in mind.
Objectives
- Define the package of battery, motor, controller, frame, rider and steering lock for an example bike.
- Develop a fairing and tank-cover form that covers the package and channels cooling air.
- Split the form into panels with shut lines and fixing positions.
- Surface panels with controlled G1 and G2 boundaries and verify them with evaluation tools.
- Export clean surfaces for engineering and produce renders.
What you need
Tools and toolboxes
- Autodesk Alias (Surface or AutoStudio) — Curve networks, panel surfaces, shut lines and evaluation.
- Alias surface tools — Rail Surface, Skin, Square, Freeform Blend, Surface Fillet, Align and Trim for panels and shut lines.
- Diagnostic Shading and continuity checks — Zebra and curvature shading plus continuity evaluation at panel boundaries.
- IGES/STEP export — Hand-off of surfaces to SOLIDWORKS for thickening and mounting design.
- VRED, KeyShot or SOLIDWORKS Visualize — Presentation renders.
Software
- Autodesk Alias 2024 or later
- A renderer
Extra parts and data
- A reference motorcycle to measure — Real handlebar, footpeg and seat positions give a believable rider triangle.
Key concepts
- Panel break-up
- Dividing the form into separate mouldings that can be produced, fitted and removed for service, with joints placed where they help the design.
- Shut line
- The visible gap between two panels. Consistent gap width and a return flange make it look intentional.
- G1 and G2 continuity
- G1 means matching tangency at a boundary; G2 also matches curvature, giving smoother highlights on large visible surfaces.
- Steering lock clearance
- The fairing must clear the handlebars, forks and rider's hands at full lock, which often limits fairing width.
Step-by-step guide
- 1
Build the package
Model the frame, an example 5 kWh battery box, motor, controller, wheels, forks and the rider triangle as simple bodies or curves, with the steering turned to full lock left and right as separate references. Use measured or published values for seat height, footpeg and handlebar position. Mark where the battery and controller need cooling air in and out, and where the charging port sits.
Checkpoint: Package geometry in Alias layers with steering-lock positions and a stated source for each dimension.
- 2
Sketch and choose a direction
Sketch fairing and tank-cover ideas over a side view of the package, exploring stance, the line from headlamp to tail and how the battery area is expressed rather than hidden. Think about where air enters at the front and leaves behind the battery and controller. Produce at least three ideas, choose one, and annotate it with the airflow paths and the panel joints you imagine.
Checkpoint: A sketch sheet with at least three ideas and a chosen one annotated with airflow paths.
- 3
Lay out key curves
Build the side profile, plan outline, main section curves and a primary feature line with low-span CV curves of moderate degree. Keep the curves consistent between views by projecting or intersecting them rather than drawing each view separately. Check curvature combs on every curve and remove reversals that are not part of the design, rebuilding a curve if its comb looks noisy.
Checkpoint: Main curves with clean combs and consistent intersections in all views.
- 4
Define panel break-up
Draw shut-line curves on the form to divide the front fairing, side panels, tank cover and tail. Place them along feature lines or in shadow areas so they look intentional, and allow service access to the battery, fuse box and charging port. Plan where each panel fixes to the frame and the direction in which it is removed, since that affects flanges and clips.
Checkpoint: A panel layout drawing with every panel named and its fixings and removal direction noted.
- 5
Surface the primary panels
Create the large visible panels first with Rail or Square surfaces, keeping isoparms aligned with the main flow of the form. Work with symmetry about the centre plane. Use Align to set G1 continuity between neighbours at first, then G2 on prominent boundaries such as the blend from tank cover to side panel, where reflections are most visible to a viewer.
Checkpoint: Zebra stripes flow smoothly across G2 boundaries with no visible kinks.
- 6
Create shut lines and flanges
Trim the panels along the shut-line curves, then offset each edge back to create a consistent gap, for example 3 mm as a design value. Add return flanges behind each edge with Rail surfaces so the gap looks solid from normal viewing angles and hides the frame. Check gap width and flange depth with sections at several points along each shut line.
Checkpoint: Sections along each shut line show a constant gap within an example tolerance of ±0.3 mm.
- 7
Add openings and details
Cut and surface the air inlets and outlets, the headlamp opening, mirror and indicator mounts and the charging port door. Give each opening a return surface angled into the body so it reads with depth. Keep the openings aligned with the airflow paths planned in the sketch stage, and check that the inlet area is not blocked by the rider's knees or the forks at lock.
Checkpoint: Openings are trimmed cleanly with returns and match the planned airflow paths.
- 8
Evaluate quality and clearance
Run continuity checks at each important boundary and inspect the panels with Zebra and curvature shading from several angles. Check clearance to the package and to the forks and handlebars at full steering lock using sections and the Evaluate tools. Fix any problem by rebuilding the underlying curves rather than piling on CVs, then repeat the checks after each fix.
Checkpoint: A boundary table listing target and measured continuity, and clearance to the package above an example 10 mm at full lock.
- 9
Export and present
Export the panel surfaces as STEP or IGES and confirm they import into SOLIDWORKS and knit without gaps, ready for thickening. Render the bike in three views and a panel exploded view with VRED, KeyShot or SOLIDWORKS Visualize. Present the package, sketches, panel layout, quality checks and renders on a board, stating that it is a student concept. Keep the native Alias file with its layers alongside the exports.
Checkpoint: Surfaces import cleanly into SOLIDWORKS and a presentation board is complete.
Testing & validation
- Fairing clears the package and steering at full lock by the stated margin.
- Continuity checks meet G1 or G2 targets at listed boundaries.
- Shut-line gaps are uniform within the tolerance.
- Exported surfaces import into SOLIDWORKS without gaps.
Expected results
An electric motorcycle fairing, tank cover and side panels surfaced in Alias with a planned panel break-up, uniform shut lines, checked continuity and clearance, exported surfaces and renders.
Take it further
- Thicken panels in SOLIDWORKS and design mounting bosses.
- Run a CFD study of cooling flow through the inlets.
- Make a scale 3-D printed model.
- Design a colour and trim scheme with alternatives.
Viva and review questions
How did you decide where to place shut lines?
Along feature lines or in shadow regions, so they look intentional, and where service access to the battery and charger is needed.
Why use G2 on some boundaries and not all?
G2 gives smoother highlights on large visible surfaces, but it takes more control. I used it where reflections are prominent and G1 elsewhere.
Why check steering lock?
The fairing and the rider's hands must clear forks and bars at full lock, which often limits fairing width.
Learn it at DIYguru
These DIYguru courses and programmes teach what this project needs.