1/22 Wall Grammar for Building Generation Mathieu Larive and Véronique Gaildrat Visual Objects, from Reality To EXpression http://www.irit.fr/-Equipe-VORTEX Oktal Synthetic Environment http://www.oktal-se.fr
Slides : Wall Grammar for building generation
Jul 08, 2015
We present a new technique to automatically generate building ex-
teriors. Our technique relies on the definition of building templates
that will be applied on building descriptions. The building descrip-
tions require the building 3D footprints and their heights and roof
heights. This information can be stored within a Geographic Infor-
mation System (GIS). Most of the time, graphic designers use the
texture repetition method in order to create building frontages. Due
to this lack of flexibility, this method often disappoints the users
who expect more realism. In this paper, we focus on the descrip-
tion of our frontage generation method. Building frontages are gen-
erated using a 2.5D wall grammar based on a set of rules that can
be simple or detailed enough to fulfil the users wishes. Our method
is as easy to use as the texture repetition but provides a higher level
of realism and diversity in the resulting buildings
teriors. Our technique relies on the definition of building templates
that will be applied on building descriptions. The building descrip-
tions require the building 3D footprints and their heights and roof
heights. This information can be stored within a Geographic Infor-
mation System (GIS). Most of the time, graphic designers use the
texture repetition method in order to create building frontages. Due
to this lack of flexibility, this method often disappoints the users
who expect more realism. In this paper, we focus on the descrip-
tion of our frontage generation method. Building frontages are gen-
erated using a 2.5D wall grammar based on a set of rules that can
be simple or detailed enough to fulfil the users wishes. Our method
is as easy to use as the texture repetition but provides a higher level
of realism and diversity in the resulting buildings
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
1/22
Wall Grammar for Building Generation
Mathieu Larive and Véronique Gaildrat
Visual Objects, from Reality To EXpressionhttp://www.irit.fr/-Equipe-VORTEX
Oktal Synthetic Environmenthttp://www.oktal-se.fr
2/22
Contents
• Introduction
• Frontage Templates
• Groundwork and Roof Templates
• Results and Discussions
• Conclusion and Future Work
3/22
Problem
4/22
Goals
• Quickly create a plausible (geo-typic) city around an already modelized zone (geo-specific)
• Reach a level of detail satisfactory enough for a navigation at ground level:– modeling of the buildings’inside– geometric modeling of the urban furniture
→ usage of automatic techniques inside AGETIM
5/22
Generation steps
• Hierarchical division of city generation process in seven steps [Larive2005]
• Each step can be seen as a logical LoD
6/22
Contents
• Introduction
• Frontage Templates
• Groundwork and Roof Templates
• Results and Discussions
• Conclusion and Future Work
7/22
Frontage Templates
• A frontage template contains a primary wall and possibly a background material
• A frontage template can be seen as a style sheet that describes:– wall rendering– possible dimensions and kinds of windows and doors
(described as textures or 3D objects)– how to place these elements on the building
8/22
Frontage Templates
• Formal grammar representation [Wonka2003]
• 2,5 dimensions paramatric wall grammar
Position rulesRepetition rules
9/22
Frontage Templates
• Wall Panel
– the unique terminal symbol of our grammar
– various parameters:• texture
– Background– Decoration
• 3D object• possible dimensions
10/22
Frontage Templates
• Extruded Wall– depth (positive or not)– depth faces generation
boolean – EW → W
• Bordered Wall– four margins– resize policy– BW → W
11/22
Frontage Templates
• Wall Grid– Contains an unique
child wall– Repetition
• Vertical• Horizontal• Both
– Controlled by two cardinality intervals
– WG → Wnm
12/22
Frontage Templates
• Wall List– Several child walls– Orientation (exclusive)
• Vertical• Horizontal
– WL → W1W
2...W
n
13/22
Frontage Templates
• The combination of those different walls in a tree-like hierarchy allows the user to build simple or complex frontage templates
• Use of repetition schemes on every part of our frontages (wall grid)
• Usage of previously generated 3D objects (such as balconies or cornices)
14/22
Frontage Templates
15/22
Contents
• Introduction
• Frontage Templates
• Groundwork and Roof Templates
• Results and Discussions
• Conclusion and Future Work
16/22
Groundwork and Roof Templates
• Groundwork templates– Z-min– Z-max– Extruded
Z-min Z-max Extruded
17/22
Groundwork and Roofs Template
• Roof templates– Based on the Straight
Skeleton method [Felkel1998]
– One, two or four slopes– Overhang (4 types)– Currently, 10 various
roof types
18/22
Contents
• Introduction
• Frontage Templates
• Groundwork and Roof Templates
• Results and Discussions
• Conclusion and Future Work
19/22
Results
• Various buildings on one building footprint
94 faces 350 faces 5600 faces
20/22
Results
• Large scale urban area
17 362 buildings, 920 182 faces generated in less than 8 mn
21/22
Conclusion
• Able to generate buildings on any kind of footprint– convex, non-convex, non-plane, even with holes
• Generated buildings are valid – geometrically (no hole, no overlapping face, no empty
frontage -blind frontages-)– no window or door on a frontage edge
• Once a building template is finished and robust, it can be immediately reused (ready-to-use building template library)
• Control of the geometric complexity, according to the user hints
22/22
Future Work
• Finalize the building template editor
• Usage of the Urban Land Use Model– Road network generation– Creation of lots and
building footprints
• Integration of all the various generation steps inside the same process
Related Documents
