How Our Cutting Templates Work
Clear explanation of the CNC mitering logic used in our exploded cutting templates. This page is intended for customers who want to understand exactly how the cut lines are generated.
Why Special Logic Is Needed at Hem/Seam Corners
In our exploded cutting templates, every panel has two types of edges:
- Outer Perimeter Edges — these receive the full hem allowance (typically +50 mm)
- Internal Sliced Seams — these receive only the seam allowance (typically +20 mm)
Where these two different allowance types meet (at the corners of each exploded panel), a simple offset would often produce bad geometry for CNC cutting: inward hooks, long spikes, or incorrect seam lengths. These problems are invisible in normal viewing but can cause issues on the laser cutter.
The Hybrid Mitering Approach We Use
At every hem ↔ seam transition we use a hybrid rule that combines mathematical precision with production safety:
1. Exact Geometric Miter (when safe)
We first calculate the true intersection point of the two offset lines. When this point is geometrically valid (reasonable distance and clearly outward), we use it. This gives the mathematically correct miter.
2. Safe Hem-Side Fallback (when needed)
If the pure intersection would create a bad result (too far out, inward hook, or unstable), we fall back to the offset point calculated from the hem (outer perimeter) side. This guarantees:
- Correct seam length in the cut line
- Always-outward offset on the outer perimeter
- No self-intersections or reversals
3. Light Blend in Borderline Cases
In the small number of corners that sit between "clearly good" and "clearly bad", we apply a light weighted blend (80% toward the safe hem-side point). This produces smooth, professional transitions without visible steps or kinks.
What This Means for CNC / Laser Cutting
- Always safe to cut — no inward hooks or crossing lines that could damage the fabric or the machine.
- Correct seam lengths — the cut piece will match the intended sewn dimensions after hemming.
- Minimal manual cleanup — the geometry is already production-ready in almost all cases.
- Transparent logic — the legend in every DXF explains exactly which method was used at each corner.
Why You Might Still See Small Transitions
At some hem/seam junctions you may notice a very small direction change. This is normal and expected behaviour when two different offset distances meet at approximately 90°.
These micro-transitions are not defects. They are the result of prioritising CNC safety and correct seam length over a perfect visual miter. Laser cutters handle these small direction changes without any problem.
Our cutting templates use the most accurate miter possible while guaranteeing that every line is safe, outward, and dimensionally correct for professional CNC/laser production.
Still Have Questions?
If you see anything in a cutting template that looks unexpected, please send us the DXF file together with a screenshot. We are happy to review it and explain exactly why the geometry was generated that way.