Non-rectilinear structures dominate traditional Andean weaving patterns. A systematic description is essential for enabling weavers to document and secure intellectual property rights and for preserving their rich cultural heritage. The author presents a system for modelling non-rectilinear as well as rectilinear weaving patterns; it is the first of its kind. The authors have implemented an editor demonstrating the capabilities of the approach and show its application.
TopData Structure
The textile is viewed from the top like knot diagrams. The basic object is the crossing of two threads. A crossing identifies the thread above the other, has a position in the plane and is numbered. In addition, it has and four links (named N(orth), W, E and S) to connect it to links of other crossings, following the segments of threads between them. At the destination of each link another link points back to its origin. A thread entering a crossing at a link either exits at the opposite link or ends there (and the opposite link will be unused). Threads can be assigned a colour at a link.
This representation implies that instead of modifying the contents of a fixed grid we have three separate problems to handle. First the user has to define the topological structure of the weaving, then the crossings have to be arranged in the plane and finally the thread passing on top of the other has to be identified at each crossing.
The editor maintains two structures: the numbered list of crossings (Figure 1) and the list of the coloured links with the colours. Threads are, in consequence, represented implicitly and changing a link will change the course of the thread.
Figure 1. Left: • Simple structure. Right: • Internal representation of its crossings with crossing numbers.
Given the knowledge representation model, different users will wish for different interfaces to edit the same structure, for instance a non-weaver would use different operators to create a structure than the weaver who knows how it was woven.
TopThe Editor
The editor has three display modes for the structure: full structure (Figures 5 and 6), structure and coloured threads (Figure 1), coloured threads only (Figure 2, 1 – 4 from left, Figure 7 right, Figure 8). It also has a rendering mode (Figure 2 right, Figure 3). Rendering mode became necessary as commercial CAD programs refused to render tens of thousands of thread segments (determining all the occlusions being the likely problem).