Creating depth in shallow-relief porcelain sculptures requires a blend of technical skill and artistic vision. Here are the most effective techniques to achieve striking dimensionality:

1. Layered Carving: Build depth by carefully carving multiple layers into the porcelain, starting with subtle outlines and gradually deepening key areas. This mimics natural shadows and highlights.

2. Textural Contrast: Combine smooth surfaces with intricately carved textures. Rough areas appear to recede, while polished sections advance, enhancing the illusion of depth.

3. Angle Variation: Adjust carving angles to manipulate light reflection. Steeper angles create deeper shadows, while shallow cuts maintain delicate details.

4. Undercutting: Strategically remove material beneath raised edges to cast natural shadows, amplifying the 3D effect without excessive depth.

5. Glazing Techniques: Use translucent glazes on recessed areas and opaque finishes on raised portions to optically enhance depth perception.

6. Perspective Tricks: Employ foreshortening in designs, making distant elements slightly smaller and less detailed to simulate spatial recession.

7. Clay Density Control: Work with porcelain at optimal dryness - slightly leather-hard provides enough firmness for precise carving while preventing collapse.

The key lies in balancing these methods to maintain the integrity of the delicate porcelain while achieving remarkable visual depth. Successful pieces often combine three or more techniques, with master artists sometimes spending weeks perfecting just a few square inches of relief work.

Remember that lighting plays a crucial role in displaying shallow-relief sculptures. Directional lighting at 45-degree angles maximizes the depth illusion created through these techniques. With practice, these methods allow artists to transform flat porcelain surfaces into breathtaking dimensional artworks.