Triangular bike bag — builder and test patterns
Test · side zipper · four attachments · Dimensions, 3D model, and PDF A4, SVG, DXF patterns at 1:1 scale.

Test 350 × 220 × 65 mm. Two triangular walls, one circular strip, four attachment straps. Before cutting, trace the available space of the specific frame and check the clearances; position the straps and zipper according to the mock-up. An independent test construction based on the shape, not a copy of a commercial pattern.
Open this example in the designerThe example opens with the dimensions specified below. Its changes are saved separately from your regular work. You can return to it using the link in the editor.
Example source parameters
Linear dimensions are given in millimeters. Parameter names match the designer fields; these are the initial settings and can be changed.
| Parameter | Value |
|---|---|
| Body width | 350 |
| Body height | 220 |
| Body depth | 65 |
| Leather thickness | 1.5 |
| Stitch offset from edge | 4 |
| Additional seam allowance | 0 |
Parts in this example
The dimensions below are derived from the geometric model. The parts list changes with the parameters and enabled options.
| Piece | Size, mm |
|---|---|
| Zipper panel | 350.0 × 220.0 |
| Back panel | 350.0 × 220.0 |
| Circular side panel | 983.4 × 65.0 |
| Strap · frame-strap-0 | 165.0 × 18.0 |
| Strap · frame-strap-1 | 165.0 × 18.0 |
| Strap · frame-strap-2 | 165.0 × 18.0 |
| Strap · frame-strap-3 | 165.0 × 18.0 |
How the size changes the pattern piece
Calculated example: the “body width” parameter was changed from 350 to 385 mm. The diagram shows the “Wall with zipper” piece before and after recalculation at the same scale.
You can also download the modified JSON project. After modification, check the assembly on a mockup.
Download the pattern example
The files were generated using the standard VLOTHO CAD export from the parameters specified above. They show the model geometry and do not replace checking the product in the material.
PDF A4, 16 sheetsPDF patterns, 1:1SVG patterns, 1:1DXF patterns, mmJSON project
PDF A4 automatically selects portrait or landscape pages and rotates the pieces to reduce the number of sheets. For assembly, a 10 mm overlap, numbers, and alignment marks are provided. The standard PDF contains one piece per page. Both variants include a 100 mm test segment. For your own dimensions, modify the project and export a new PDF. How to print patterns at 1:1 scale.
What to check before cutting
The dimensions are preliminary. First assemble a paper mockup, then make a trial piece from inexpensive material. Not verified by sewing.
VLOTHO CAD builds a geometric prototype. Allowances for bending, skiving, assembly thickness, and construction methods are determined by your material. Start with a paper mockup and a trial piece.
How to get a pattern for your dimensions
- Open the model and set the dimensions in millimeters. To reproduce the tabular example, first load its JSON.
- Check the parts list and enabled options. Adjust the seam and dimensions for your material.
- Save the project and export a new pattern set. After changing the dimensions, the previous files no longer correspond to the project.
Dimension reference for this model: Stitching line. Dimensions in the parts table and the outer cut contour may differ due to the seam allowance. How to check seam allowances and stitching lines.
Materials and assembly
Select the leather thickness and stiffness, seam allowances, and hardware on a mock-up. Image — a generated illustration of the construction.
File preparation
Printing patterns on A4 at 1:1 scale · DXF units and layers before cutting
Next step
Construction and export instructions · Manual contour editing · All models