Trace and Blob Tracking Effect with TouchDesigner

I've been seeing this effect a lot lately and thought I'd figure out how its done and share it.
This tutorial covers lots of other fun little techniques using a Cache TOP and Difference TOP to make a cheap motion detection TOP.
If there's an effect out there that you'd like to learn. Send it my way.
Support me on Patreon for access to the source files and more:
patreon.com/DeanCheesman

[@jimdeblock]

good stuff. thanks Dean. following! I'll have a think about suggesting another technique for your next tutorial

[@DeanCheesman]

Thanks for the feedback!

[@alinak_2023]

Thank you for your tutorial!!! I have trouble connecting null and geo, can u please explain

[@DeanCheesman]

Of course! By default a geo doesn't have a SOP input on it, but if you take a sop and drag a wire from its output and hit tab to see the operators, then choose a geo it will add the input for you and connect it.

[@alinak_2023]

@@DeanCheesman thank u!

[@maladroit8520]

Where would I have to go (virtually or otherwise), or what courses would I have to take to learn how to do all this?

[@DeanCheesman]

You’re already there! It’s all pretty much available to learn here on KZbin!

[@guillots]

Hi there! great tutorial. I'm having a little problem when i connect the last null(4) with the text1 node. The numbers appears at the bottom left of the render. I suppose its not taking the information of the blob tracker. (im using the non-commercial version of TD). Do you have any tip? thanks! =)

[@DeanCheesman]

Hey thanks for following along. Two potential reasons I can think of. Did you convert your blob's u and v to x and y positions by multiplying by your height? Also did you make sure that your column names in null4 are exactly "x", "y", and "text"?

[@harman4686]

having the same problem, even after the suggested solutions

[@harman4686]

I think I found a solution, change your position value to fraction aspect from pixels in the text sop

[@guillots]

@@DeanCheesman I think I found the error. I did the tutorial again from blobtracker and I think I had forgotten to multiply by the height of my video (1280). Thanks!