Weathering Steel Structural Assembly Animation

A material whose key property is invisible until years have passed

Weathering steel develops a stable oxide layer — a natural patina — when exposed to the atmosphere. This patina acts as a barrier against further corrosion, eliminating the need for paint or ongoing maintenance. The colour changes from black through to light and dark orange over months and years.

The Hobson Engineering Structural Assembly is a three-piece bolt, nut, and washer set manufactured from Redcor weathering steel, used in bridges, stadiums, and road and rail infrastructure. The brief was to animate what the product does — and what makes it different — for an audience of engineers, architects, and designers.

The product's defining feature happens over years, not seconds

The primary advantage of weathering steel is its patina — a gradual colour change from black to orange that forms over months and years of exposure. No photograph can show this. A data sheet can describe it, but describing a colour change and showing it are entirely different things for an audience evaluating structural materials.

The animation needed to compress years of weathering into seconds, while keeping the colour progression technically accurate and visually clear — without the background competing with the product.

Built from a SolidWorks assembly file, sequenced around the colour change

Hobson Engineering provided the SolidWorks assembly file. The animation opens with an exploded product view showing all three components, moves into the assembly sequence, then transitions into the timelapse colour-change sequence.

The background was desaturated throughout the colour-change sequence so it doesn't compete with the product. The colour progression — black to light orange to dark orange — was animated as a smooth continuous transition independent of the season cuts, so the change reads as a material property rather than a lighting effect. A diagonal wipe transition was used between sequences to maintain visual momentum.

Rusty patina textures were applied in the final render pass to match the reference material provided by the client. On-screen text was kept minimal: product name and "Natural Patina. No maintenance required."

Sequence shown in the animation

• Exploded product view — bolt, nut, and washer components shown separately
• Assembly sequence — components joining into structural connection
• Timelapse with season progression — time passing shown in background
• Colour change animation — black to light orange to dark orange over years
• Patina texture — rusty surface finish matching real weathering steel reference
• On-screen text — product name and key product claim

Shown at the AUSTROADS Bridge Conference, Brisbane

The final animation was delivered the evening before the conference and shown the following day on a 3×2m stand shared with BlueScope at the AUSTROADS Bridge Conference in Brisbane, June 2025. The audience was structural engineers, architects, and designers.

Hobson Engineering published the animation on LinkedIn alongside event coverage of the stand. The video is in use across trade shows, LinkedIn, and the product website.