random dots plugin

Rosilari's Avatar

Rosilari

22 May, 2015 03:53 PM

Hi Chris,
I've been playing around a bit with the random dots plugin.
It works fairly well.
I only have a couple of questions about it.

As i understand, it misses a wrap-around parameter (i.e., when a dot that hasn't finished its lifetime moves outside the stimulus aperture, it isn't redrawn on the opposite side). Does the plugin provide a new dot in a random position, in this case? Otherwise the density could vary a bit at each frame...

How did you compute the random directions of the non-coherent dots? I had the impression (but I understand it can just be an impression) that some directions are more represented than others and this creates "streams" of randomly moving dots along few directions.

Finally, I tried to copy&paste the plugin in the MW 0.5.1 version, but of course it didn't work (it gave me an 'Unknown attribute "announce_stimuli_on_implicit_updates"' error). Is there any way to use the randomdots plug-in in a non-nightly build version of MW?

Hope everything is clear!
Thanks in advance
Bw
Rosilari

  1. Support Staff 1 Posted by Christopher Sta... on 22 May, 2015 08:46 PM

    Christopher Stawarz's Avatar

    Hi Rosilari,

    As i understand, it misses a wrap-around parameter (i.e., when a dot that hasn't finished its lifetime moves outside the stimulus aperture, it isn't redrawn on the opposite side). Does the plugin provide a new dot in a random position, in this case?

    When a non-expired dot drifts out of the field, a new dot drifts in. The new dot is assigned a random direction and age (subject to your specified coherence and lifetime), so it can enter the field at any location compatible with its direction.

    How did you compute the random directions of the non-coherent dots? I had the impression (but I understand it can just be an impression) that some directions are more represented than others and this creates "streams" of randomly moving dots along few directions.

    For non-coherent dots, the plugin picks the direction by drawing a random floating-point value from a uniform distribution over the range [0, 360).

    Is there any way to use the randomdots plug-in in a non-nightly build version of MW?

    No, it's only available in (and compatible with) the nightly build.

    Cheers,
    Chris

  2. 2 Posted by Rosilari on 23 May, 2015 01:44 PM

    Rosilari's Avatar

    Thanks a lot!
    Rosilari

  3. Christopher Stawarz closed this discussion on 26 May, 2015 01:46 PM.

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