Bridges, especially elevated road bridges, differ from rail models because they are not flat but three-dimensional. Therefore, an interlocking sense of depth needs to be created, primarily through variations in color depth, contour lines, and shapes. There are two main methods: the three-dimensional modeling technique and the two-dimensional modeling technique. The two-dimensional technique is typically used when the bridge is an accessory. To showcase the bridge itself, the three-dimensional technique is generally employed, as it clearly demonstrates the size and elevation of the bridge. Specific methods are as follows:

1. Hierarchical Representation: Display the height, dimensions, and levels of the bridge using contour lines. The color progression from light to dark from top to bottom during painting, along with the creation of shadow areas, enhances the visual realism.

2. Width Representation: During the construction of bridges, the width can be emphasized through visual illusion. It is not necessary to shrink them proportionally; instead, certain widths can be intentionally exaggerated to create a distinguishable sense of width in the visual appearance of the bridge.

3. Perspective Representation: Since we usually view models from above, the green belts and guardrails on both sides of the bridge should be made taller to ensure they are visible.

4. Fixed Model: Once the model is completed, it must be securely fixed to the base platform. Therefore, the assembly can be done in sections, ensuring that each segment is not overly long. Reinforce the joints for added stability, ensuring the model remains firm.