[Visualpython-users] visual timing problem

[Goedele V. B. <goe...@ps...>]

Hi,

I am a researcher in visual perception, more precisely we are 
investigating transsaccadic change blindness. This means we change the 
position of an object in a 3D scene, during an eye movement. Afterwards 
the viewer has to indicate whether or not he notices something was 
replaced. Therefor it is very important this position change occurs 
during the eye movement, and not after it.

We are using VPython to display the scene, because it is so nice to use. 
But there is a slight problem with it. An eye movement takes about 30 
msec, and detecting it takes about 12msec. This means there is only 
about 18msec left to change the display. The problem with Visual is that 
the display is only refreshed 20 times per second, which means there can 
be 50msec between the command of changing the position, and the update 
of the cache.

Is there a way to change this 20 times per second? (where can I find 
it?) Would it still work if I update the video memory myself, every time 
I change something in the scene, or, when I update the video memory 
every msec? And where is the command for updating the video memory given?

Regards,

Goedele Van Belle

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