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W. Huang, M. Williams, D. Luo, Y. Wu and Y. Lin (eds.), Learning, Prototyping and Adapting, Short
Paper Proceedings of the 23rd International Conference on Computer-Aided Architectural Design Research
in Asia (CAADRIA) 2018. © 2018, The Association for Computer-Aided Architectural Design Research in
Asia (CAADRIA), Hong Kong.
DRAWING WITH BOTS: HUMAN-COMPUTER COL-
LABORATIVE DRAWING EXPERIMENTS
HAO ZHENG
University of California, Berkeley, USA
pt990platina@berkeley.edu
Abstract. When drawing architectural images like plan drawings, de-
signers should always define every details, so the images can contain
enough information to support a design. However, the core information
in a complex design is usually very simple. For example, in a plan draw-
ing of an office building, what we really care is the boundary and func-
tion of each room, rather than the exact location of furniture should be.
So here, we propose a method to help designers automatically generate
the predicted details of architectural drawings, based on Conditional
Generative Adversarial Network (CGAN). Through machine learning
of hundreds of image pairs, the learning program will build a model to
find out the connections between two given images, then the evaluation
program will generate an output image according to the new input im-
age we provide. Four experiments about generating architectural plan
images and city satellite images will be introduced in this article. The
final goal for this method is to assist designers to simplify drawing pro-
cess, and eventually to replace designers to self-draw architectural and
city images.
Keywords. machine learning; image generating; self-drawing; archi-
tectural drawing; CGAN.
1. Introduction
1.1. BACKGROUND AND PROBLEM DESCRIPTION
When drawing architectural images like plan drawings, designers should al-
ways define every details, so the images can contain enough information to
support a design. However, the core information in a complex design is usu-
ally very simple. For example, in a plan drawing of an office building, what
128 H. ZHENG
we really care is the boundary and function of each room, rather than the exact
location of furniture should be.
However, recently, machine learning, as a decision making tool, is being
developed in many fields. It can be used to analyse large amount of data, and
predict the future changes.
So, this article discusses one of the machine learning algorithms, Condi-
tional Generative Adversarial Network (CGAN), helping designers simplify
drawing process at the beginning stage of a design.
1.2. CGAN INTRODUCTION
Goodfellow et al. (2014) proposed a new framework (GAN) in machine learn-
ing, and trained model G for generating data and model D for estimating the
possibility that the output data comes from original training data. To maximize
this possibility, the program trained model G, and finally G reached a situation
that, D can’t distinguish the data generated by G from the original data.
Soon, Mirza and Osindero (2014) refined the framework, and proposed
Conditional Generative Adversarial Network (CGAN), which introduced ex-
tra information y as additional input layer. The objective of a CGAN can be
expressed as
LcGAN(G,D) = Ex,y[log D(x,y)] + Ex,z[log(1-D(x,G(x,z))] (1)
Recently, Isola et al. (2016) applied CGAN to image-to-image translation,
proposed an efficient method to build connection between image pairs and
predict possible corresponding output image of a given input image (Figure
1).
Figure 1. Example results by Isola et al. (2016).
So, based on the work done by Isola et al. (2016), we propose a new appli-
cation of CGAN in generating architectural drawings and city satellite images
in this article.
2. Generating images of architectural plan drawings
The first thing we tried is to build a connection model between architectural
plan drawings and its core information.
DRAWING WITH BOTS: HUMAN-COMPUTER COLLABORATIVE DRAWING
EXPERIMENTS 129
2.1. TRAINING BY BOUNDARY
We got 800 floor plans from the Columbia University database, which were
student assignments or exhibition works at the Department of Architecture in
the 1960s. The corresponding input image is the boundary of each plan (Figure
2).
Figure 2. Training data – plan drawing (left) and boundary block (right) [Data from Artstor
collection (http://www.artstor.org/)].
Then we generated random block area images as input images to test the
performance of this connection model (Figure 3). It recognizes the outer walls
perfectly but the inner area still seems blurry.
Figure 3. Output data – predicted architectural plan drawing (left) and input boundary block
image (right).
2.2. TRAINING BY FUNCTION
However, boundary information is not enough to record a plan drawing. So
we used different colours to represent different areas as input images (Figure
4). Here, Black represents the indoor boundary, yellow represents the interior
area, cyan represents the furniture area, and red represents the architectural
axis.
130 H. ZHENG
Figure 4. Training data – original plan drawing (left) and corresponding coloured image
(right).
Then we drew coloured images of new plan drawings, and used the con-
nection model we built to predict the architectural plans (Figure 5). As the
figure shows, with more information, the new connection model can make
more detailed prediction. This model performs better than the former model.
So by giving simplified images, designers can easily generate complex archi-
tectural plan drawings.
Figure 5. Output data – coloured image (left), predicted image (middle), and original draw-
ing (right).
3. Generating images of city satellite photos
Next, we tried to use same algorithm to test its performance with larger data.
While architectural plan drawings are very hard to collect, city data, such as
satellite images and street view images, are easier to grab from the Internet.
3.1. TRAINING BY BOUNDARY
So first, we grabbed the vector information and satellite photos in a city of
Florida from Google Map. A program loaded the data, and found out all closed
curves and their corresponding satellite images. After cleaning useless infor-
mation, the training set contains only boundary blocks and satellite images
(Figure 6).
DRAWING WITH BOTS: HUMAN-COMPUTER COLLABORATIVE DRAWING
EXPERIMENTS 131
Figure 6. Training data – satellite image (left) and city block boundary (right).
We then gave the program boundary images in another city, and asked for
a prediction image (Figure 7). It shows that the connection model well pre-
dicted the common features of city in Florida, and it’s totally different from
those in Barcelona City.
Figure 7. Output data – boundary image (left), predicted image for Florida (middle), and
original image in Barcelona City (right).
3.2. TRAINING BY FUNCTION
Next, we added further information about a city to the input images. We
distinguished different blocks by their characteristics with different colours
(Figure 8). Here, red means buildings, green means green lands, blue means
water or pool, and white means others.
Figure 8. Training data – satellite image (left) and city information image (right).
Based on the training data from three cities, Barcelona, Manhattan, and
London, we built three models to predict the most possible satellite images of
a given coloured map, which was drawn by hand (Figure 9). So also, by giving
sketches, designers can get the predicted satellite photos as a preview of city
images.
132 H. ZHENG
Figure 9. Output data – sketch image (left), predicted image of Barcelona (middle left), pre-
dicted image of Manhattan (middle right), and predicted image of London (right).
4. Conclusion
As described above, Conditional Generative Adversarial Network (CGAN)
performs well in predicting architectural images. Designers can cooperate
with computer programs, by providing this system with simplified infor-
mation or sketches, get complex drawings. It liberates designers from heavy
drawing work at the beginning step of designing, and has potential to become
a more powerful tool, not only to support designers, but also to change the
design process.
Acknowledgements
I'd like to show my gratitude to Prof. Kyle Steinfeld from UC Berkeley, who supervised me in
this research, and Prof. Weixin Huang from Tsinghua University, who gave me a lot of advice.
References
Goodfellow, I., Pouget-Abadie, J., Mirza, M., Xu, B., Warde-Farley, D., Ozair, S., ... & Bengio,
Y. (2014). Generative adversarial nets. In Advances in neural information processing sys-
tems (pp. 2672-2680).
Mirza, M., & Osindero, S. (2014). Conditional generative adversarial nets. arXiv preprint
arXiv:1411.1784.
Isola, P., Zhu, J. Y., Zhou, T., & Efros, A. A. (2016). Image-to-image translation with condi-
tional adversarial networks. arXiv preprint arXiv:1611.07004.