freehand

1. ADJ A freehand drawing is drawn without using instruments such as a ruler or a compass. 徒手画的[ADJ n]

...freehand sketches. ...徒手画的草图。

2. ADV Freehand is also an adverb. 徒手画地[ADV after v]

Use a template or stencil or simply do it freehand. 用一个模板或模具，抑或索性徒手画。