 
Summary: EUROGRAPHICS 2010 / T. AkenineMöller and M. Zwicker
(Guest Editors)
Volume 29 (2010), Number 2
Inverse Procedural Modeling by
Automatic Generation of Lsystems
O. St'ava1
, B. Benes1
, R. Mech2
, D. G. Aliaga1
and P. Kristof1
1Purdue University, USA 2Adobe Systems Incorporated, USA
Abstract
We present an important step towards the solution of the problem of inverse procedural modeling by generating
parametric contextfree Lsystems that represent an input 2D model. The Lsystem rules efficiently code the regular
structures and the parameters represent the properties of the structure transformations. The algorithm takes as
input a 2D vector image that is composed of atomic elements, such as curves and polylines. Similar elements are
recognized and assigned terminal symbols of an Lsystem alphabet. The terminal symbols' position and orientation
are pairwise compared and the transformations are stored as points in multiple 4D transformation spaces. By
careful analysis of the clusters in the transformation spaces, we detect sequences of elements and code them
as Lsystem rules. The coded elements are then removed from the clusters, the clusters are updated, and then
