效果图 of indoor spiral staircase

Quick answer：

An indoor spiral staircase design illustration typically showcases a staircase with a circular or spiral shape, integrated into an indoor space. These staircases are popular for their space-saving design and aesthetic appeal. They often feature intricate railing designs and can be constructed from various materials like wood, metal, or glass. When looking for an 'effect drawing' of such a staircase, one would expect to see a detailed and realistic image or rendering that captures the staircase's design elements, proportions, and integration with the surrounding environment.