Drawing a Transparent Hemisphere with Interactive Rotation

Drawing a transparent hemisphere with interactive rotation support in MATLAB is a valuable 3D visualization technique, particularly suitable for scenarios requiring spatial structure display. The following sections explain the implementation approach step by step and demonstrate how to extend it to a full sphere. Transparent Hemisphere Implementation Strategy Basic Hemisphere Generation: Use the `sphere` function to generate coordinate matrices for a unit sphere surface, which by default returns full sphere data. By extracting the upper half portion (Z-coordinate ≥ 0), you can obtain a hemispherical surface. Adjusting the number of vertices (n parameter in sphere(n)) controls the smoothness of the hemispherical surface. Transparency Configuration: When plotting the hemispherical surface using the `surf` function, set transparency through the `FaceAlpha` parameter (e.g., 0.5 for semi-transparency). It's recommended to simultaneously adjust edge line transparency using `EdgeAlpha` to prevent grid lines from appearing too prominent. Interactive Rotation Support: After enabling the `rotate3d on` command, users can directly rotate the graphic by mouse dragging. For programmatic viewpoint control, use the `view(az,el)` function to dynamically adjust azimuth (az) and elevation (el) angles. Extension to Full Sphere Technique To draw a complete sphere, remove the Z-coordinate filtering condition and plot the full spherical surface directly. Add lighting using the `light` function to enhance three-dimensional perception, combined with `material shiny` to create reflective effects on the sphere's surface. Important Considerations Transparency effects may reduce rendering performance in complex scenes, so consider appropriately simplifying mesh density. Color mapping (using `colormap`) can be combined with transparency to distinguish data values across different regions of the spherical surface using color coding. This visualization method is suitable for applications such as geographical data presentation and optical model simulations. By parameter adjustment, it can be flexibly adapted to various requirements. The implementation leverages MATLAB's built-in 3D graphics capabilities while providing customizable transparency and interaction features.