TexGen

Abstract

This chapter gives an overview and introduction to the use of TexGen, open source software developed at the University of Nottingham as a pre-processor for 3D geometric modelling of textile structures. An overview is given of the modelling theory used in the software. There is a guide to creating automatically generated textile models using the built-in weave wizards and a detailed example of the method for creating a textile model using the functionality within the graphical user interface (GUI). An overview of the Python application programming interface (API) is given, illustrated by an example script, as well as information on how to use the Python functions to edit existing textiles. Finally there is an overview of the options for different meshing and export options used to prepare models as input for simulations.

Appendix

Exercise 1 Solution

• 1. Either select Textiles-> Create Weave… from the main menu or Weave from the Textiles tab of the Controls menu.

• 2. Set the number of warp and weft yarns to 4 (to create a 4 × 4 satin weave).

• 3. Use the warp yarn data to set the yarn spacing and yarn width (as these parameters are different for the warp and weft yarns the weft dimensions will be set later using the Pattern Dialog). The Yarn Spacing is set to 1.0 based on 10 yarns/cm.

• 4. The combined heights of the yarns is 0.5 mm so this is selected as the Fabric Thickness. The wizard will automatically set both yarn heights to 0.25 mm (half the thickness) but, again, these can be adjusted in the Pattern Dialog. Steps 2–4 are shown in Fig. 27.

• 5. Click the Next button to move to the Weave pattern dialog.

• 6. Shift-click on the bars at the left side of the weave pattern to select all of the warp yarns.

• 7. Right-click on one of the selected side bars to show options to change yarn parameters for these yarns (Fig. 28)

• 8. Select Set yarn height… and enter the value 0.3 (Fig. 29)

• 9. Repeat steps 6–8 to select the bars at the top of the weave pattern and set the weft yarn width, height and spacing to 0.7, 0.2 and 0.769 respectively. (The spacing is calculated using 13 yarns/cm)

• 10. Click on the crossovers on the weave pattern to create the desired weave configuration (Fig. 30)

• 11. Select OK. The textile is created as shown in Fig. 31. The textile can also be loaded from the Ex2_9_1.tg3 file.

Fig. 27

2D weave wizard yarn parameters

Fig. 28

Options to change selected yarns in Weave Pattern Dialog

Fig. 29

Dialog to input yarn height for selected yarns

Fig. 30

Weave configuration for Exercise 1

Fig. 31

Exercise 1, finished textile

Exercise 2 Solution

• 1. Either select Textiles-> Create 3D Weave… from the main menu or 3D Weave from the Textiles tab of the Controls menu.

• 2. Select the Orthogonal weave type and select Next.

• 3. Fill in the weft, warp and binder data as shown in Figs. 32, 33 and 34. In the binder yarn window select the Refine option and set the Target Thickness to 1.4.

• 4. In the three subsequent windows set the yarn properties. This is shown for the weft yarn in Fig. 35.

• 5. In the final weave pattern window click on the points on the binder yarns to create the desired weave configuration (Fig. 36)

• 6. Select OK. The textile is created as shown in Fig. 37. The textile can also be loaded from the Ex2_9_2.tg3 file.

Fig. 32

Weft yarn input for Exercise 2

Fig. 33

Warp yarn input for Exercise 2

Fig. 34

Binder yarn input for Exercise 2

Fig. 35

Weft yarn properties for Exercise 2

Fig. 36

Weave configuration for Exercise 2

Fig. 37

Exercise 2, finished textile

Exercise 3 Solution

• 1. Either select Domain-> Edit Domain… from the main menu or Edit from the Domain tab of the Controls menu.

• 2. The x and y dimensions of the domain are to be changed so the first four planes (ie the first four lines in the dialog) need to be changed. Select the first row. The values from this row will be displayed in the x, y, z and d text boxes. Set the d value to 2.5 and select Replace Plane. Note that the values in the main window are not updated until Replace Plane is selected.

• 3. Repeat step 2 for the next 3 planes as shown in Fig. 38.

• 4. Select OK. The size of the domain will be updated and the newly specified region of the textile will be displayed as shown in Fig. 39. The updated textile can be found in Ex2_9_3.tg3.

Fig. 38

Domain planes for Exercise 3

Fig. 39

Exercise 3, textile with domain specified for two repeats

Exercise 4 Solution

Fig. 40

Exercise 4, finished textile

The amended script can be found in Ex2_9_4.py and the resulting textile is shown in Fig. 40. The changes are as follows:

• 1 & 2.
• 3.
• 4.