Professional | Ali Seiffouri

Case Studies

Houzz

Procedural Home Decorations

One of the features of the mobile application of Houzz is "View in my room". This features enables the users to virtually see a realtime 3D model of the product they intend to purchase on their iPhone or Android device. There are literally millions of actual products in Houzz's database, transforming all of which requires a lengthy process and significant costs.

After joining Houzz I realized that many of those 3D products could be generated procedurally. Such as pillows, carpets, wall decorations, mirrors etc.

I designed an automated pipeline which generated more than 1.75 million procedural assets in less than two months. (This time could have been reduced to three weeks. The reason will be explained shortly). Assuming 20 USD per each model If outsourced, this pipeline cut the costs for more than 350,000,000 USD, not even considering the time factor.

This system was designed to minimize the human interaction as much as possible. The whole pipeline is orchestrated by Python. The first part, gathering the necessary data for the product, includes:

Connecting to Houzz's database API and finding the correct categories
Finding the products in the above category which don't have a 3D model
Acquiring and parsing the JSON data for every product
Refining the data and removing dependencies and anomalies
Export a CSV file

There are many dependencies in measurements and length units and sometimes those data don't simply exist! That is due to the fact that those information are usually entered into Houzz's database directly by the manufacturers of the products. Therefore I had to come up with a few algorithms to sift through data or extract data from the images of the products. Without this issue the the production could have been much faster.

Basically the only information needed for making each model is its image, width and height. The depth is guessed from the overall shape and the other two existing dimensions. These information is sent to Houdini for generating 3D objects based on the contour of the images. Sometimes the images are slanted and are straightening in Houdini before creating the object. The result is an optimized game-engine ready 3D model with clean topology and UV. A cleaned up texture is also generated as a bi-product.

These models and textures are then imported into to Maya and with Python. A Meta Node with holds the necessary information for Houzz engine is added. Also a material is assigned and exported as a JSON file. The scene is then saved as a Maya ASCII file (.ma). At the end all the generated files are now ready to get checked into Perforce and sent to the engine.

The image below shows the abstract model of the pipeline

An abstract representation of Houzz Procedural Asset Pipeline

Below are a few samples of the 3D assets generated by this pipeline. As you can see the contour for each product is unique and follows the actual product's contour. The third image in each group is the photo of the actual product in Houzz website.

Procedural 3D assets generated with Houdini

based on actual products

Vanity Template Generator

Vanities are one of the most important categories in Houzz's marketplace, thus needed more attention. Because of the complexity and uniqueness of vanities, they are created manually. Every 3D asset starts with basic shapes which is the scaffold of the model. Creating a suitable base takes some time for the artists; beside the general resemblance measurements should be taken care of precisely.

I designed a procedural vanity generator in Houdini and shipped it to Maya with Houdini engine. This tool allows the artists to design a base 3D model by entering the measurements and tweaking parameters. Below are some samples each of which is created in less than five minutes

Procedural vanities: a Houdini digital asset shipped to Maya as a plugin

This tool is pretty flexible and can replicate most of the vanities on the market, even curved ones. One of the main challenges was finding a way for generating the drawer patterns. This tool makes it very easy for the artists to create a base grid and then connect the selected pieces with a simple click of the mouse. The drawers are also cut out from the body in real-time while the artist is using the tool. Each template could be saved as a preset for later use. This tool has the potential to be expanded to other products such as tables and desks, chairs, closets and shelves.

Art Pipeline Tools

One of the responsibilities of a technical artists is creating tools for artists to facilitate their work and save their time. Maya is the main 3D software of the art pipeline at Houzz, therefore I wrote most of the in-house tools for Maya and created toolbars and designed icons for them.

Proprietary Maya tools for Houzz art pipeline

Many of the mentioned tools saves artists time by cutting down the manual steps they have to take to get to the desired result. For instance in the first row of the toolbars in the image above, Houzz tools, there are buttons to check-in the scene including the textures, materials and the generated metadata to Perforce within a click. Other tools do some necessary background work that could not be possible without coding. For instance the Meta-Data node which carries all the information of the scene is not available manually.

The second row, Art Tools, beside the usual utilities there is an asset browser (Widget Browser) for browsing the commonly used models which appear in a lot of furniture, like knobs, faucets, handles etc. (hence the name). This tool which is created with PySide (basically a free version of PyQT, now embedded in Maya) also enables the artists to add the models they have created into the library with a simple click; an icon is then created on the spot and everything gets checked into Perforce.

The interface of the Widget Browser tool

Implemented in Python & PySide

There are material editing tools as well dedicated to creating Physically Based Materials (PBR) and accessing the materials files stored in the internal material library as JSON files. The artists are also able to add the materials they use the most onto their own personal toolbar.

The interface of the Material Browser tool

Implemented in Python & PySide

After a tool is written and used by artists for a while, they might find specific cases that might break the tool which was not initially predicted. Some other times they need to add more features to a certain tool. Updating and maintaining these tools are the ongoing task of a technical artist which have a lot of interesting challenges which lead to a better understanding of the system and the needs of the artists.

Procedural tools for PGA Tour

The need for procedural content creation for games is increasing more than ever. The is the result of growing demand for generating more assets in less amount of time with more control and the ability of reiterating their production. Recently more artists and technical artists are recognizing the real value of procedural content creation and therefore trying to learn, expand and embed that workflow in their pipelines. EA is not an exception. It could easily be observed that how many procedural tools have been created over the last few years.

With the fast transition of the golf game (PGA Tour) to Frostbite, procedural methods became a necessity for generating or regenerating many of the assets one of which is the Terrain. Generating terrain has always been one of the main concerns for the PGA Tour as it is the core of the game; so is the Vegetation. Also some fantasy courses required procedural Rocks. These are an example of tools in Houdini that are developed for the PGA Tour game which are explained here.