踩 vs 踏: Both mean 'to step on,' but 踩 is more colloquial and often implies accidentally stepping on something. 踏 is more literary and deliberate. Also: 踩刹车 (step on the brakes) and 踩油门 (step on the gas).
Left foot radical (in its compressed running-form). Originally a pictograph of a leg with a knee and a foot at the bottom. It supplies the meaning: an action done with the feet - to step on, tread, trample. The foot radical anchors a large step-and-walk family: 跑 (run), 跳 (jump), 跌 (stumble), 踏, 跨, 踩.
Right 采 supplies the sound - exact match cǎi with no drift. 采 itself shows a hand 爪 reaching down to a tree 木, picturing someone plucking fruit; that 'pluck' meaning is incidental here, read for sound. Same phonetic family includes 彩 (colour), 睬 (heed), 菜 (vegetable), 踩.
