surface sketch

例句：

1. 1. The artist created a surface sketch of the building before starting to paint it.
   艺术家在开始绘画之前，先绘制了这座大楼的表面草图。
2. 2.During the design phase, the engineer made a rough sketch of the new bridge.
   在设计阶段，工程师绘制了新桥梁的粗略草图。
3. 3. The writer used his surface sketches as a guide for his final draft.
   作家使用他的表面草图作为他最终稿件的指导。