An Ivy Generator

by Thomas Luft

University of Konstanz
A few months ago I was looking for a new sample scene to test watercolor renderings. I was thinking of something complex, filled with vegetation - like trees overgrown with ivy. Fortunately I was able to implement a procedural system so that the ivy would grow by itself. The result is a small tool allowing a virtual ivy to grow in your 3d world.

The ivy grows from one single root following different forces: a primary growth direction (the weighted average of previous growth directions), a random influence, an adhesion force towards other objects, an up-vector imitating the phototropy of plants, and finally gravity. This simple scheme reveals that the goal was not to provide a biological simulation of growing ivy but rather a simple approach to producing complex and convincing vegetation that adapts to an existing scene. The ivy generator imports and exports obj+mtl files.

Here are precompiled versions for Win32, MacOS, and Linux including the source code of this project under the GNU General Public Licence. The MacOS port was kindly done by Robert Templeton (Kuroyume's DevelopmentZone). The Linux port was kindly done by Ruben Lopez. Previous releases and additional stuff can be found in the download section.

ivy_generator_Win32_1.3.rar (4,259 KB) (23.03.07)
ivy_generator_MacOSX_1.3.zip (8,797 KB) (23.03.07)
ivy_generator_Linux_qt4_1.3.tar.gz (2,873 KB) (28.03.07)

Feel free to use this tool in your projects! See also the FAQs!
The IvyGenerator v2/beta is still postponed.

Copyright (c) 2007 Thomas Luft. Last changes October 6, 2008.
Pavel Zoch
 Konja Urban(?)
 Tim Ellis
 Heika Hartela
 József Lipka
 Kirk Dunne
Rainer Schmidt
 Curt Roth
 Daniele Del Grande
 Doro Forster
Baz Mazur(?)
 Frédéric Boullier
 Antonio Casado
 Dieter Waibel
 Tom Schuelke
Marcus Wengenroth
 Brian Looney
 Mark Dunakin
 Joăo Félix
 Dave Davidson
 Jérôme Prévost
 Nicolas Wirrmann
Grunio(?)
 Leonardo Merlos
 Marco Mosetti
 Michael Betke
 André Vieira
 Helton de Oliveira
Jader(?)
 Tudor Schinagel
 Anthony McLin
 Hong Jin P
 Peter Christiansen
 Ziv Qual
Richard Perrine
 Marion Goldschmidt
 Alejandro Ruano
 Dan Robo
 Derya Genç
 Giorgio Macellari
 Vitek Lasota
Berthold Grünhagen
 Daniel Ackermann
 Espen Harildstad
 Jimmy Gunawan
 Davide Guldoni
Thilo Ewers
 Dinamo Productions
 Diego Emanuel
 Robert Seidel
 Peter Guthrie
Ramon Zancanaro
 Marcin Zemczak
 Camille Lymer
 Michael Ball
 Marc Gutowski
 Dean R. Robitaille
Federico Zimbaldi
 Csaba Kanal
 Székely Tamás
 Andreas Dietz
 Mads Droschler
Adán Martín
 Camille Lymer
 Krzysztof Cebula
 Dmitry Levin
 Gandoza
 Bjorn Malmberg
 Oliver Hatton
Szabolcs Csaszar
Thank you very much for your stunning feedback and the beautiful renderings!

Download
ivy_generator_Win32.rar (4,259 KB) (15.03.07)
ivy_generator_Win32_1.3.rar (4,259 KB) (23.03.07)
ivy_generator_MacOSX.zip (10,565 KB) (18.03.07)
ivy_generator_MacOSX_1.2.zip (10,565 KB) (20.03.07)
ivy_generator_MacOSX_1.3.zip (8,797 KB) (23.03.07)
ivy_generator_Linux_qt4_1.3.tar.gz (2,873 KB) (28.03.07)
ivy_generator_Textures.zip (7,006 KB)
set of textures including normal maps etc., kindly provided by Tim Ellis (sonix(at)btconnect.com)
Ivy Generator tutorial
explains first steps using the Ivy Generator, kindly provided by Mark Dunakin (MD arts)
Ivy Generator & Blender tutorial (at 4shared.com)
explains how to use the Ivy Generator in combination with Blender, kindly provided by Tim Ellis (sonix(at)btconnect.com)

Frequently asked questions
May I use the Ivy Generator in a commerical project? May I use my results (renderings and meshes) in a commerical project?
Yes, you are allowed to do that.

Can I somehow support this project?
Yes, you can. Please, visit www.loim.de/ivy_generator_donation

Is there a manual for this tool?
The current release of the Ivy Generator contains only a basic instruction (see readme.txt). Future releases will of course have a more detailed manual.

The import does not work properly - my scene looks somehow cluttered. What can I do?
The current release of the Ivy Generator supports only triangular faces. Thus, you have to triangulate your mesh before importing.

The ivy is growing very slow. What can I do?
Please consider the possiblity of using simpler proxy geometry for the Ivy Generator. The growing performance depends strongly on the complexity of your scene.

I can't see the ivy growing - it is growing inside my objects. What can I do?
Please press "flip normals" after importing your scene, and try again.

Is it possible to create another ivy without closing and re-opening the Ivy Generator?
Simply place a new root - double-click in your scene. Then the existing ivy will be deleted and you can grow a new one.

The exported files are HUGE. What can I do?
Future release will provide LOD techniques for this complex kind of mesh. By the way, you don't have to wait until the ivy is completely grown - by pressing the "grow" button again, you can stop it whenever you want.

The exported files are empty. What can I do?
Please press "birth" before exporting.

Can you please implement feature x?
The current release of the Ivy Generator is unsupported. Feel free to send me your feedback for future releases.

Do you plan to write a plug-in for software x?
Future releases will have a plug-in friendly software structure. If you are interest in writing a plug-in version for a specific package, please let me know.

Does this software run on a 64bit operating system or Microsoft Vista?
The current release was not tested on such a system so far.

I can not see any textures within the Ivy Generator?
Some former graphic cards do not handle textures of arbitrary size. Please, try to rescale the textures to a power of two format, e.g. 256 x 256 pixels.

I did not find an answer...
Feel free to write me an email ;-)