Fashion Turntable

Load geometry and explore it in 3D space. In this project, we were interested in 3D scanning textile materials close enough to see stitching and individual threads. This featured garment by Mook Attakanwong is one of 25 models.

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Background

As a part of their final year project UTS fashion students are required to make 5 garments. This includes making their own materials and textiles for the garments and then showcasing them on a runway.

All textiles were scanned as well as the garment itself. The fashion garment was placed on a mannequin. 300 photographs were then taken from different angles around the garment.

Pairs of Cameras

Pairs of DSLR Cameras were rigged (see right) side-by-side to capture "image pairs"; two similar photographs. Features from each photo are compared. The slight differences recorded. Based on these distances, and the known characteristics of the camera lens, the position of each feature is determined as a point in 3D space. A 3D point cloud is created.

Neighbouring points in the 3D cloud are connected by edges to form triangles. This forms a triangular mesh surface model. We have a 3D triangle model of the garment. To colour the triangles the same photos are then re-projected (texture-mapped) onto the surface from the same original angle to produce the real-looking 3D model. The apparent detail comes from the hirez photos, not the geometry which is fairly low resolution.

The 3D model was obtained by using Photoscan by Agisoft, which was fairly new in 2014. These days there are many ways to obtain a 3D model from a sequence of images.

We experimented with various camera separation distances (14cm to 130cm), as shown in the video below. This is the gap between the pair of cameras. 14cm was the closest we could mount them turned 90-degrees side-by-side in portrait mode. We found there was a sweet-spot for the separation which best handled cloth materials with many folds. Generally, the greater the camera separation the lower the ability to match features in the pictures from the two cameras.

The photogrammetry rig

This project was made possible through the construction of a 3D camera rig, comprising left and right side cameras to create a stereo image. The Data Arena team made an excursion to Bunnings (a local hardware store). We bought garden hoses and shopping trolley wheels to construct the camera rig.

The garden hoses were placed in two concentric circles on the ground. They're used as guide rails for the wheels which were attached to the camera rig. Two wheels are held between the hoses. The "circular dolly" rig was used to photograph the dress. Features from the digital photos were compared on computer to create a 3D point cloud. These points are then stitched together on a computer using photogrammetry software. The photos are then projected back onto the wireframe surface model to achieve the result seen on screen.