Bridges, especially flyover models, differ from railroads as they are three-dimensional rather than flat, requiring an interlocking layer effect. This is primarily conveyed through color depth, contour lines, and shapes. There are two main methods: the three-dimensional method and the flat method. The flat method is usually used when bridges are accessories, while the three-dimensional method is preferred to showcase the bridge itself, clearly illustrating its size and elevation. The specific methods are as follows:

Layered Representation: Display the height, dimensions, and layers of the bridge using contour lines. During painting, the color transitions from light to dark from top to bottom, and shadows are created for a more realistic visual effect.

2. Width and Narrowness Representation: During the manufacturing of bridges, visual errors can be utilized to differentiate widths rather than strictly following a proportional scale. By intentionally enlarging certain widths, the bridges can visually convey the distinction between widths.

3. Perspective Representation: Since we usually view models from above, the green belts and guardrails on both sides of the bridge should be made higher, otherwise, they may be easily overlooked.

4. Fixed Model: The completed model must be securely fixed to the base platform, allowing for the application of adhesive in sections. This ensures that each segment is not overly long and that the joints are reinforced, ensuring the stability of the model.