Automatic TOP Cropping in TouchDesigner - Tutorial

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Cropping is such a vital part of texture processing. Especially when you're creating dynamic content it can be difficult to constantly figure out how to crop in tightly around an object. In this video, Elburz takes you deep into CHOP processing and operators that pros use on a daily basis such as Shuffle CHOP, Analyze CHOP, and TOP to CHOP so that you can build a fully dynamic network that will automatically delete unused areas of an image or movie where there is no alpha content!

[@Tanya_Mist]

It helps me a lot!! Thank you!!

[@TheInteractiveImmersiveHQ]

So glad to hear that! Thanks for watching :)

[@LealRaulAndres]

Great video thanks. I do not know what changed since you made the video but i had to make some tweeks to get it fully working. I wanted to move the image horzontally and vertically so not fully. Here are my comments for the ones that come after me.
- Somehow, i did not have to substract the width or heifgh form the indexes that i was getting. so all my expression on the crop are like op('nullCrop')['right'], for each corner.
- i had some issues when the image was going out of the boundaries, all them where solved by turning off "allow start peaks" and "allow end peaks" on the analyse's where you peak the peak index
- the only part where i had to use the dimensssions was on the anlyse for the bottom had to put "No peak value" to the height.
Again txs and i hope others benefit from this commets,

[@TheInteractiveImmersiveHQ]

Just wanted to confirm that the method Elburz uses in the video works in TouchDesigner 2022.35320 with no modifications! I would double check and see if you missed any steps or settings along the way, as the operators used in the technique haven't changed significantly since the video was recorded.
A couple of easy to miss changes include removing the R, G, and B channels from the TOP to CHOP (leaving only alpha) and setting the units of each parameter of the Crop TOP to Pixels. Hope that helps! :)

[@hakandurgut]

👏👏👏👏👏

[@truefiasco2637]

useful tool, but when I can't crop with math or data I do it in tops. no reason why you can't take the alpha channel and multiply it with a uv map with analyse min max for the red and green channels and get your data that way.

[@TheInteractiveImmersiveHQ]

Absolutely. There are tons of ways to achieve this and this is more important as an example and exercise in using CHOPs more than it is a specific tool you might want to use in large scale productions. A lot of folks never ever really get into shuffling TOP data and using it in interesting ways, so this can help people start thinking about that!