Hi Jianhao,
As shown in the Usage line in the help (the link that you sent), you need the "models" keyword to limit the action to certain models, e.g. to rotate model #1 only:

turn y 180 models #1

I hope this helps,
Elaine
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Elaine C. Meng, Ph.D.                       
UCSF Chimera(X) team
Department of Pharmaceutical Chemistry
University of California, San Francisco

> On May 3, 2021, at 3:36 PM, C.J. <biocjh@gmail.com> wrote:
>
> Hi all,
>
> I tried "turn y 180 #1" (https://www.cgl.ucsf.edu/chimera/docs/UsersGuide/midas/turn.html) but it doesn't work. It said "turn frame arguement must be an integer".
> While I tried "turn y 180 0 #1" or "turn y 180 1 #1", it said "wait_frames arguement not implemented". Even "turn y 180 0 0 #1" doesn't work. Did I miss something?
>
> Thank you!
> Jianhao