First TOP after feedback chain doesn't function normally

I’m trying out a feedback tutorial and not exactly sure how to describe this bug: I wanted the final output of a feedback chain to be blurred, and for some reason the blur effect seemed to be changing something within the chain instead, until I added another TOP in between the null (feedback target at the end) and the blur effect. In the attached file, when I bypass the HSV adjust, the blur2 at the end totally changes behavior.

water pool feedback.toe (5.2 KB)

I tried your example file and do not see that. If I delete blur1, blur2 does not have any effect on the feedback regardless of hsvadj1’s state. Could you explain further?
(Moved to general)

hmm, that’s a scenario I didn’t try, but I think I’m not explaining where the problem was… was just hypothesizing that blur2 had some effect on the chain based on what happened.

the problem I was having was when trying to view blur2 as the final output of the patch; it didn’t behave like a blur without the hsvadv (doing nothing) in between null and it. With hsvadv on, I get smooth black-to-white gradient type blurring, and with it bypassed, I get some kind of effect that looks like the way blur1 is affecting the feedback chain, still with only regions of all white or all black. Hard to explain what is going on, but the version with hsvadj seems like the correct behavior.

here’s what I see with hsvadj on (normal blurring):

and with it off (similar to blur1):

Oh I see now. This is the result of your TOP chain being in 16-bit float pixel format (this occurs inside the sharpen effect you are using). The 16-bit float gives you image pixel values ranging from -64000 to +64000.

The HSV Adjust TOP clamps values between 0-1, so it changes the data going into the Blur. HSV Adjust does this for a few reasons, but most other TOPs do not. Note the Level TOP’s first parameter is “Clamp to 0-1”, this has the same effect.

So the Blur TOP is indeed working and blurring with the HSV Adjust bypassed, but you can not ‘see’ the blur because viewers and your monitor are all 8-bit (okay, maybe you have a fancy 10-bit monitor, but its not common). You can see the blur at work in the Blur TOP if you make the ‘Viewer Active’ and turn on the Normalized Split viewing mode. This doesn’t change the data, it just normalizes the range of pixel values to 0-1 so you can see the effect here.

Another way to you can inspect the values on the pixels in your image is to attach a TOP to CHOP to your TOP of interest.
Hope that answers why it is happening, now the question is what effect you want to go with?!

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Ah, thanks so much! I was starting to guess it was something like that, but had no idea of the terminology here or where to check. Also thanks for mentioning level, I was looking for some of that stuff (and the step section seems like a less convoluted way to do some of this).

I definitely wanted the blurred output so I could try using that feedback loop as a whirlpool-like displacement map, but now that I know what’s going on there’s some more experimenting to do!