1. He decided to scratchbuild his own model airplane instead of purchasing a pre-built one.

他决定自制一架模型飞机，而不是购买一架预制的。

2. The architect scratchbuilt a scale model of the building before constructing the actual structure.

建筑师在建造实际建筑之前，自制了一个建筑的比例模型。