This workshop cluster, a part of the 2018 Smart Geometry Conference hosted by the University of Toronto, brings recent developments in machine learning (ML) to bear on generative architectural design. To improve the utility of artificial intelligence as a creative partner for design, we have brought together experts from architectural design practice, ML engineering, and design methods research.

Over the course of this workshop, participants train purpose-built image-based ML models to evaluate candidate design solutions based on a variety of tacit and heretofore un-encapsulatable design criteria, such as architectural style, spatial experience, or typological features. Participants then deploy these models to the cloud, and integrate them into functional generative design systems via API calls.

Seeking to validate and extend previous work¹ in which local spatial compositions are captured and identified using machine learning, an ML model is trained to distinguish a given set of spatial configurations given an unrolled 2d image of a 3d isovist. This model is deployed in the service of tuning a parametric model to produce new and unexpected combinations of spatial experience.

Using a corpus of 3d models, an ML model is trained to distinguish between and classify architectural massings related to a single programmatic type: the detached North American single family home. To accomplish this, a method is developed to translate sliced CAD models into sets of related images able to be understood by ML processes. This model is deployed in the service of discovering potential new and compelling massings that hybridize known types.

A building's shape is the most influential factor in mitigating wind effects. Using results from tests that were performed at SOM's wind tunnel in Chicago, the WT 260, an ML model is trained to assess the behavior of tall buildings under wind loads based on building shape and orientation. Massing models at a 1:500 scale are positioned at the back of the wind tunnel on a load cell that measures different parameters such as frequency, displacement and forces. For the purposes of training the ML model, this data has been interpreted and organized into five different qualitative categories of behavior under wind loads: bad, fair, moderate, good and excellent. This ML model is deployed in the service of helping designers to better shape buildings for wind loads and potentially offering new ideas to improve their performance.

To maintain focus on the evaluation of candidate designs using ML models, technologies necessary for a rudimentary generative design workflow have been prepared in advance of the workshop and are quickly introduced to participants.

Technical Overview of the Basic Workflow

We establish a workflow that allows us to focus on the unique contribution of the cluster: the development of methods for the integration of ML evaluation routines into a parametric environment. To proceed as a generative design workflow, the three basic concerns outlined above must be addressed. As an overview of the software involved, these are addressed as such:

This approach fits easily into the common skill-set of most digitally-motivated architects, and we expect workshop participants arrive with basic parametric modeling skills.

Here is where much of the work of the cluster lies. Here we must establish training datasets via a variety of methods (some of which require scripting in Python), train image-based models using Tensorflow, host these models on cloud servers dedicated to this purpose, and establish structures to call upon them using an application program interface (API). In support of this workflow, we have partnered with Lobe.ai, a visual programming language for creating neural networks. Using the Grasshopper-like graphical programming environment provided by Lobe, workshop participants are able to design a model, use a pre-trained one, and receive predictions from the cloud.

By pitting actor against critic, using existing tools such as Galapagos, Opossum or similar, the space of possible designs (defined by the actor) is iteratively explored in order to identify the best performing solutions (in the eyes of the critic). To this end, a toolset has been established that supports the integration of a trained and hosted ML model into a general generative design workflow. A set of components in Grasshopper are provided that construct API calls to the hosted model, receive results, and processes this information into Grasshopper compatible data.

As we discuss below, certain problems arise with the conversion of three-dimensional information, as is so often employed in the production of architectural work, to two-dimensional information, as is required by the particular models of ML based on image recognition that we are exploring here. To isolate these problems, this first example operates in a purely two-dimensional fashion.

Training the Critic

An Initial Critc

An initial set of ML models were trained on this dataset of 9,900 images organized into 99 categories of 10 samples each. A number of image resolution were tested: 20px, 50px, 100px, and 200px.

After training was complete, we found two problems.

First, the accuracy of our models, which varied from 58% for the 20px images to 73% for the 200px images were not satisfactory.

Second, the given organization of the leaf shapes left something to be desired from a design point of view.

A Revised Critic

As we were interested in encapsulating the the formal characteristics of leaf forms, and not in identifying leafs in terms of the species of tree to which they belong, the existing structure of this dataset did not quite suit our ends.

A second model was then trained on this re-organized dataset of leaf shapes.

After training was complete, the model presented an accuracy of 81%.

Defining the Actor

Blackblob

Metaball

Metaspike

Orchestrating an Optimization