5 ms·

What keeps the lines from intersecting? Is that a property of "Perlin noise"?

• wetmore 6y ago
  I think it comes from the noise field being relatively smooth, and the particles taking such small steps each frame.
• kmm 6y ago
  The flowlines of any vector field cannot intersect, because that would mean the flowline has two tangent vectors at that point. For smooth vector fields, they cannot merge either, an intuition for that is perhaps that you could theoretically run the flow "in reverse", which would turn a merger into a split, and that's not possible.
  • bhickey 6y ago
    'Procedural Landscapes with Overhangs' by Gamito and Musgrave covers exactly this! http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.2.1625&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.2.1...
  • efsfwer 6y ago
    The Perlin noise is generating a scalar field in this case (which gives the direction of the movement vector at each point). Here's a very similar bit of code that can be tweaked easily: https://openprocessing.org/sketch/494102/ https://openprocessing.org/sketch/494102/ Setting the particle speed to more than about 0.5 (on line 46) results in "aberrations". The dynamics are quite interesting and I'm not sure exactly what's going on, but I think wetmore's answer is correct—when the steps are small enough, everything remains as smooth as the underlying scalar field produced by Perlin noise.