Grasshopper

algorithmic modeling for Rhino

# reaction diffusion on triangular mesh

This is a vase modeled via Rhinoceros, meshed with quad with Rhino, re-meshed using Kangaroo in order to have triangular mesh. The mesh is re-meshed in the script in order to have enough triangles (400k). A classic reaction diffusion is applied on the mesh. The script is provided but beware it is quite long (10 min) because of Sandbox which is used  to get all neighbor vertex of each vertex.

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The simpliest thing is to replace équation with 0.055 or whatever kill rate you want.

+1

Here is the explanation of the generation of generation of Cactus
Beware : Disable solutions script is almost 3 minutes long

First I draw 3 curves, one for the trunk (one radius) and 2 for branches (same radius). I used David Stasiuk Cocoon in order to make the shape.
http://www.bespokegeometry.com/2015/07/22/cocoon/

After being happy with the shape I toggle the final generation of mesh from Cocoon with a subd of 1 (126,792 faces).

I then calculate direction I want for the pattern, here the same directions as the nearest curve. Surely not the smartest way of doing but it works.

After that Reaction Diffusion could be used. A good site to understand is
http://www.karlsims.com/rd.html
A good site to choose feed and kill values is
http://mrob.com/pub/comp/xmorphia/index.html

In order to modify the size of the pattern I use B diffusion and also the size of the mesh.
The directionality is controlled by _factor > 1 and pattern will follow tangents, and < 1 pattern will be perpendicular to the tangents.

Here differents parameters to play with

This script could surely be used to replicate Nervous Reaction design, thanks to them to their creativity.
http://n-e-r-v-o-u-s.com/

Laurent Delrieu
August 2015

Attachments:

Here is a more simple script with a triangle as example.

2 mains entries :

1) a triangular mesh with equilateral triangles (remeshed with Kangaroo mesh machine for example)

2) curve(s) in order to compute the direction of the pattern

Attachments:

Very cool Laurent, thanks for sharing.

Thanks Daniel, I hope it could be useful for you to design beautiful jewellery like Arothron Mappa ring.

I have my own code with very good results, but your focus will be really helpful when returning to this issue. If I get a new contribution thanks to you, I will publish the result. ;)

http://www.grasshopper3d.com/photo/arothron-mappa?context=user

This is all really wonderful, awesome job Laurent! Thanks so much for sharing it.

Great and thorough explanation!

Hi,

I needed some reaction diffusion so I used your script as a starting point and refactored it to make use of classes and made it multithreaded. It should be faster, more readable (at least for me) and easier to add more things to it.

Some values are hardcoded in the script but should be easy to find.

And the script

Attachments:

Thanks Vicente

It works very well and is simple to use. It is very interesting to see a different way of programming and to discover multithreading. I have to study that.

Best regards

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