[Thomas Hannen]

Hi,
I’ve used a technique before where you use a 4 point gradient. You place nulls in a square around the logo, on the colour of the shirt at the corners but not touching the logo.

You 2D motion track the logo, and use the track to move the four nulls.

You use an expression to continuously get the RGB values at the four corners, color sampling at those points on every frame.

Place a solid over the video and mask it to cover the logo.

Track the position of the solid using the motion track you made earlier.

Apply a four point gradient to the solid, where the four sets of RBG values are driven from the colour sampling expressions you made earlier.

Feather the edges of the solid’s mask.

I can’t remember the exact expression, or where I saw this technique, but I used it years ago and it worked well, because as the shirt moves it subtly changes colour.

See Tristan’s example here :

https://forums.creativecow.net/thread/2/970410

[Thomas Hannen]

Scary bug…

Just had exactly the same problem in CS6, and your solution works – thanks!

In case anyone else has to look it up – you can trash the prefs in CS6 by holding down CMD+OPTION+SHIFT when you click the icon to open AE.

[Thomas Hannen]

Thanks Thomas. Would the pipeline method be quicker though? Is Media Encoder having to recalculate everything in After Effects to make the second pass, or does it keep some kind of pixel-perfect cache in order to make the multiple output versions?

[Thomas Hannen]

Just to let you all know, this is what the problem was – infinitely thin shapes don’t appear in AE.

If you extrude them slightly, this solves the problem.

I believe this is known as “rubber ducking” 🙂
https://en.wikipedia.org/wiki/Rubber_ducking

[Thomas Hannen]

The more I look at it, it seems to be because the “dish” in the image above is very thin – possibly only one “vertex” thick.. I think this is what’s causing the problem, so I’m going to attempt to extrude the dish a bit, and see if it fixes it…

[Thomas Hannen]

Yes it does, and I could do that, but I was wanting to try using the objects directly in AE, as I haven’t managed to use the Live3D mode successfully before. I’ve also go Trapcode, so could go the Mesh route using Form, but was hoping to find out why this isn’t working…

Cheers,
Tom

[Thomas Hannen]

I’ve had this problem before too. I don’t know why it happens.. One possible workaround is to deliberately add a tiny amount of noise to areas within the image where the banding is occurring. It’s not a great idea, as it increases the file-size, and effectively reduces the available bandwidth for the rest of the image, but sometimes it looks better than the alternative.

[Thomas Hannen]

Thanks Dan,
Would this work down through nested comps recursively?

[Thomas Hannen]

You can also bounce particles off from up to 2 surfaces using Trapcode Particular. Mentioning this in case you already have it. Newton sounds like a better choice in this instance, but I haven’t used it. I believe there are also some very complicated ways to do this using the built in particle plugins, but involves lots messing around with displacement layers shaded to bounce from (see some of the Foam tutorials).

[Thomas Hannen]

Hi – I think this tutorial by the amazing SebBap is probably what you’re looking for:
https://greyscalegorilla.com/blog/2011/03/de-sync-expressions-tutorial-by-sebastian/

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