TP Texture Edge detection tutorial:
Having the ability to build effects based on the outlines of a shape is very important in VFX and motion graphics, so I made this easy to follow setup to detect image edges and create particles on top. You can control the width, threshold and the samples.
It's better if you download the tutorial files at the bottom of this page and follow along, because my description wasnt that detailed.
First step is to sample the surface by creating lots of particles using matterwave, I didn't use the surface position node because Matter wave gives a better particle distribution and if you wanna make them random you do so easily. So you create an object and apply the texture you wanna trace then create Matterwave and pick your object:
-Choose Pistol shot instead of count and check per Emitter.
-Set the speed to 0 and an enough life span.
-Expose U and V emitter inputs and connect them to a float helper, this will control samples density.
-Expose U and V Random inputs and connect them to a float helper, this will control samples Randomness.
Second we wanna store the surface color in a memory per particle so each particle will store the color beneath it.
Second we wanna split those particles into two groups (Black,White), so we will call the color that we stored previously and hook it to a threshold condition. This flow (as shown in the pic below) will allow you to animate the Edge color value so if you are not going to use animate it then it's better to use a particle age to stop it from checking the color every frame.
This clip shows the animated (Edge color value), I used a noise map here with lots of gradients instead of the (B&W TP above) to show the threshold moving, and also that you can use what ever color you want.
Third step is to add a distance condition between the Black and White group which will move the particle to a new group called Edge. I used PPassAB for this task and the more the distance value the thicker the edge is.
You can use this setup with any kind of effect you want in the example below I used it with Volume Breaker which gave a very nice results.
And here it is applied to the TP bitmap with an aimated width......
To wrap it up:
If you have any question plz feel free to comment or email me I will be glad to help.
Alaa Alnahlawi. ^_^