The following are examples of growth in three dimensions based upon the same
principles as diffusion limited aggregation, normally performed in
two dimensions. The basic principle involves a particle
that moves around randomly until it gets close to part of the existing
structure, at which point it sticks and becomes part of the structure.
The process is started with a seeding structure, normally a single point, and
continues until the structure reaches a desired size.
Click on the images here for higher resolution versions
Exhibited at Museum of Design, Zurich.
einfach komplex – Bildbäume und Baumbilder in der Wissenschaft.
Simply Complex -- Picture-Trees and Tree Pictures in Science.
30 April 2005 -- 4 September 2005
The renderings here are created using POV-Ray, each particle is actually represented
as a cone and a piecewise Bezier curve is used to smooth continuous chains of
particles. As particles are added the thickness of the branch leading to that
particle in thickened.
A further extension is to constrain the DLA growth to some "vessel".
In the following the constraint takes the form a box (left) or
cylinder (right) with one end open.
Grown over a sphere (planetarium), left: looking from inside the planetarium,
right: from the outside of the dome.
DLA grown within a 3D scanned model of the human head (plus antlers),
described by a STL file.
Part of modelling exercise for Philippe Vranjes.
The software presented here is made available for Mac OS-X, for
Mac OS-X X-Windows must be installed and running. DLA structures can be grown in 3D,
constraint surfaces applied, and resulting structures saved in PovRay format for
high quality rendering.
Screen dump from dla3dviewer
Resulting render from PovRay (Unmodified from export)
The following downloads are fully functional except saving of the
geometry is disabled and size of growth is limited is limited to 4000 branches.
The software is provided for a number of versions of Mac OSX, please contact
the author if you experience problems.
This allows you to check the software, the unrestricted
version is available for a modest shareware fee.
Buy full version
> dla3dviewer -h
Usage: dla3dviewer [command line options]
Command line options
-h this text
-f full screen
-s active (quad buffer) stereo
-ss dual screen stereo
left rotate camera
middle roll camera
Function keys: see menus
h reset camera
[,] roll camera
<,> more camera forward, backward
+,- zoom camera in, out
w window dump to TGA file
Screen dump from dla3dviewer
Resulting render from PovRay
The software expects a three button mouse, note that under Mac OS-X the middle
and left button can be activated by using the option and control keys. The left
mouse button rotates the camera about the model, the middle button rolls the camera,
and the right button brings up a menu system.
Useful keys include the '<' and '>' keys for moving the camera towards to away
from the model. The camera is always pointing towards the origin which is where the
initial seed particle is placed.
Using the menus the distribution of the introduced particles can be varied, the
default is to introduce new particles on the surface of a sphere. When "extras"
are turned on the last few thousand positions of introduced particles are shown.
Particles are introduced just past the maximum range of the current model.
Random seed: Each seed creates a unique structure, alternatively the same
structure will result from the same seed (all other conditions being equal).
Bias towards origin: On each timestep the current particle moves in a random
direction, the bias movies the particle towards the origin, generally by a very small
Branch length: This sets the scale of the model and is the length of an added branch
as well as defining how close a particle needs to get to the existing DLA structure
in order to "stick" to it.
Stickiness: This is the probability of a particle sticking to the existing DLA
structure once it is close enough. In general this control determines the density
and fuzziness of the final structure. More information.
Particle rotation: On each time step this rotates the current particle about the
z axis by (usually) a very small angle. Adds a swirling effect to the DLA and can
vary the fractal dimension.
Branch thickness: This is used when the DLA structure is drawn with solid branches,
instead of lines and points. This is also used in most of the export formats. The
minimum value will be the thickness of the end of the branches.
Intersection range is used to avoid self intersections.
Multiple roots can be created, the range is used by the
built in root seed distributions distribution.
The constraint surface can be scaled, translated, and rotated.
Growth inside a cup
Physical realisations of various growth stages by David Sutton.
Multiple independent seeds
Each growth acts as a constraint on others
Further examples by David Sutton
Project by Michael Eden, building DLA structure within Architectural elements.
Constrained Diffusion Limited Aggregation in 3 Dimensions
Poster: Graphite (ACM Siggraph), Dunedin November/December 2005
Diffusion Limited Aggregation (DLA) has usually been studied in 2 dimensions as a
model of fractal growth processes such as branching, lightning, snowflakes,
mineral deposits, and coral. Here, the basic principles are extended into 3
dimensions and used to create believable models of root systems. A
straightforward approach is introduced for constraining the growth of the 3
dimensional DLA by a surface or containing it within a vessel.