Instruction For This Project: You Need To Do The Coloring.

Instruction for This Project You Need To Do The Coloring On The Object

Instruction For this project, you need to do the coloring on the object surface to make a more realistic 3D look. Recall what we have learned in the class, there are three types of illumination models: diffuse, ambient, and phong terms. So you need to apply these three illumination principles to generate a plausible RGB color for each 3D unit. Since the bunny object consists of multiple triangles. For this assignment, you need to use the flat shading mode to render the Bunny object. In other word, the shading unit is a triangle. All the surface points from the same triangle have the same RGB color. see the attachments.

Paper For Above instruction

The objective of this project is to apply fundamental illumination models—ambient, diffuse, and phong—to achieve realistic shading on a 3D object, specifically the Bunny model, using flat shading. Flat shading simplifies rendering by assigning a uniform color to each polygon (triangle), which is determined based on lighting calculations at the polygon's surface. This approach emphasizes the faceted appearance of the model, aligning with the requirement that each triangle shares a common RGB color.

To implement this, it is crucial to understand the three core components of the illumination models. Ambient lighting simulates the scattering of light in all directions, providing a base level of illumination that ensures no part of the object appears completely dark. Diffuse lighting represents the matte surface reflection, depending on the angle between the light source and the surface normal, adding depth and realism. Phong reflection includes specular highlights, which depend on the viewer's position relative to the reflection vector, creating shiny spots on the object.

The first step in the process involves calculating the surface normals for each triangle, as these normals are essential for the lighting computations. The normal can be derived from the vertices of the triangle using cross products, which gives a vector perpendicular to the surface. After obtaining the triangle normal, you proceed to compute the ambient, diffuse, and specular components for each triangle individually.

For the ambient component, a constant ambient coefficient multiplied by the ambient light color is used. The diffuse component is calculated based on the dot product between the normalized normal vector and the normalized light source vector, representing how directly the surface faces the light. The Phong specular component involves reflecting the light vector about the normal and then computing the dot product with the viewer's direction, raised to a shininess exponent to control the highlight size.

Since the assignment specifies flat shading, all surface points of a triangle will share the same color, which is the sum of the ambient, diffuse, and specular components, clamped within valid RGB ranges. This unified color emphasizes the faceted nature of the shading, making the model's geometry conspicuous.

Once the per-triangle color is computed, rendering proceeds by filling each triangle with this color, ensuring that the surface shading accurately reflects the lighting conditions. This process enhances the 3D realism of the Bunny model, illustrating clearly how light influences the appearance of surfaces in virtual environments.

In conclusion, this project underscores the importance of mesh normals, lighting calculations, and shading techniques in 3D rendering. Flat shading employing ambient, diffuse, and phong lighting models offers a straightforward yet effective way to visualize the impact of lighting on complex geometries like the Bunny, facilitating a better understanding of shading and illumination principles in computer graphics.

References

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