When the viewport isolates a object, ogsRender() still renders all objects

the viewport like this: 3 objects, 1 selected(the green one).

my code:

import maya.cmds as cmds
# isolate selected object. (Ctrl+1)
cmds.isolateSelect("modelPanel4",state=True)
cmds.isolateSelect("modelPanel4",aso=True)
# snapshot.
cmds.ogsRender(h=512, w=512, cv=True, ems=True)

When I execute them one by one, the result is as expected. only the “green one” is in the screenshot.

When I execute them together, isolate becomes invalid. all 3 objects are in the screenshot.

Why??

Answer

This is because the Viewport is locked when the script is running. need to insert refresh command before the screenshot.

cmds.refresh(cv=True, f=True)