hey everyone! i'm currently learning about blob tracking and particles, and i got really interested in how nouses kou makes those lines that smoothly follow the particles like, no random jitter or jumping around. can anyone help me figure out how to do

Beginners
1

Screenshot 2026-05-10 at 00-02-45 Instagram
Screenshot 2026-05-10 at 00-02-45 Instagram530×943 210 KB

2

Hello,

A more readable example would be useful, quick answer :

  • in SOP world you need to use feedback TOP to have trails on the render (not in 3D space)
  • in POP world, you can use trail POP to materialize the trails in 3D space
3

Screenshot 2026-05-17 144643
Screenshot 2026-05-17 144643491×749 154 KB

Hello, thanks for the response! I’m having this annoying issue where my lines keep snapping to coordinate 0,0 whenever a blob isn’t detected. The lines work great when blobs are detected, but the moment a blob disappears, the lines shoot straight to 0,0 instead of staying at the last known position. How to keep the lines at the last valid position when a blob drops out? Thanks!

4

Hello,

You need to filter your blobtrack output.

Hee is a solution, with chop execute DAT to change the u, v result only when there is a detection.

Hope that helps,

Jacques

blobtrackSelector.toe (5.1 KB)

blobtrackSelector
blobtrackSelector1877×528 65.2 KB

5

Thanks a lot for the help! This works when I use the u v channels renamed to tx and ty for instancing in Geo COMP, but in my case I’m using Blob Track CHOP processed through CHOP to SOP to draw lines with Add SOP.
Here’s my file:

BlobtrackLine.toe (570.1 KB)

6

Hello,

-Trying to help you, if you post your project, please be carefull to

  • comment your project as to explain what appening for each part of it
  • name your operators accordingly
  • show where is the problem
  • lock your entries (moviefilein 1, 2 and 3) as to show what kind of image you use or use a TD map object with relative python path, or make a package with project and dependencies
  • do not superpose two operators (like moviefilein 1 and 3 or constant 7 and 9 et.)
  • in the datexec 1 and other script, change the name of operator as to have a working python

I tryied first ro have a working project (see below) but its easier to ask help if you make a project concentrating on the proper problem, not a so complicated one :frowning:

Jacques

BlobtrackLine.1.toe (590.1 KB)

7

Thanks for the help and feedback. Hope you’re having a great day. Sorry for not organizing the files better and for not being very clear when asking for help, but your suggestion to use DAT Execute made me want to try using Script CHOP, and it ended up working for my project :+1: