Guided Procedural Modeling

Abstract

Procedural methods present one of the most powerful techniques for authoring a vast variety of computer graphics models. However, their massive applicability is hindered by the lack of control and a low predictability of the results. In the classical procedural modeling pipeline, the user usually defines a set of rules, executes the procedural system, and by examining the results attempts to infer what should be changed in the system definition in order to achieve the desired output. We present guided procedural modeling, a new approach that allows a high level of top-down control by breaking the system into smaller building blocks that communicate. In our work we generalize the concept of the environment. The user creates a set of guides. Each guide defines a region in which a specific procedural model operates. These guides are connected by a set of links that serve for message passing between the procedural models attached to each guide. The entire model consists of a set of guides with procedural models, a graph representing their connection, and the method in which the guides interact. The modeling process is performed by modifying each of the described elements. The user can control the high-level description by editing the guides or manipulate the low-level description by changing the procedural rules. Changing the connectivity allows the user to create new complex forms in an easy and intuitive way. We show several examples of procedural structures, including an ornamental pattern, a street layout, a bridge, and a model of trees. We also demonstrate interactive examples for quick and intuitive editing using physics-based mass-spring system.

Evaluating procedural modelling for 3D models of informal settlements in urban design activities

“…[30][31][32][33] Urban modelling is a prominent reason for the popularity of procedural modelling, as cities are not only big, but also incredibly detailed. 34 With manual modelling, it would be too tedious and time-consuming to generate realistic 3D models.…”

“…34 With manual modelling, it would be too tedious and time-consuming to generate realistic 3D models. 33 The procedural modelling process described in this article was derived from the visualisation pipeline and adapted for procedural modelling. The visualisation pipeline defines the process required to create visualisation from raw data.…”

Generating and exploring good building layouts

“…All such methods, however, expect the user to encode the rules of the grammar, a task that is similar to implementing scripts in a professional modeling package. To simplify the rule creation process, several important ideas emerged over time: graphical user interfaces to simplify editing a grammar and the resulting models [Lipp et al 2008]; or grammars augmented to interact with external constraints, such as guidance shapes, user input, or simulation [Měch and Prusinkiewicz 1996;Prusinkiewicz et al 2001;Beneš et al 2011;Talton et al 2011]; or grammars derived from existing models, a process referred to as inverse procedural modeling [Aliaga et al 2007;Müller et al 2007;Bokeloh et al 2010;Št'ava et al 2010].…”

Procedural facade variations from a single layout

“…There are various extensions to add additional control to a grammar, such as the ability of a grammar to interact with user defined shapes [Prusinkiewicz et al 1994;Prusinkiewicz et al 2001;Beneš et al 2011;Talton et al 2011]. While grammars typically have to be written in a text editor, Lipp et al [2008] provide ideas how to specify grammars and modify designs with a graphical user interface.…”