Universal Windshield Sunshade: One Size Against Many Glass Shapes
A sunshade that actually covers the glass — sized from the observation that windshield dimensions repeat across models even when their shapes do not.
Existing foil sunshades do not cover the whole windshield and do not stay up. The client wanted a product that fixed both.
The problem
The obvious approach — a magnetic frame gripping the car’s trim — does not survive contact with a real vehicle:
- Magnets have nothing to hold. Around a windshield, the surrounding trim is usually not ferrous. A magnetic design fails on most cars in the target market.
- Every windshield is a different shape. A universal product cannot match the curvature of each one.
- Full coverage is the whole point. Partial coverage is what makes existing products annoying — light comes in at the corners.
The useful insight came from the client’s own research: while shapes differ, overall windshield dimensions repeat across many models.
The approach
- Design to the dimension, not the shape. The panel was sized against the repeating envelope so it covers the opening on a wide range of cars without trying to follow any single curve.
- Attachment reconsidered from the start, once magnets were ruled out on the physical evidence rather than after a prototype failed.
- Coverage at the edges prioritised, because corner gaps are the specific failure users complain about.
- Two iterations, with the concept revised as the client refined how the product should look and pack away.
The result
A complete design for a universal sunshade with the attachment approach resolved and the sizing logic documented — the product’s actual claim being based on a measurement, not on a hope.
Where this applies
Aftermarket accessories that must fit many vehicles. The design question is always which dimension is common enough to build a product on.
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