> For the complete documentation index, see [llms.txt](https://docs.quilter.ai/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.quilter.ai/design-parameters/net-widths-by-layer.md).
# Net Widths by Layer
### Net Widths by Layer
In general, Quilter's development philosophy is to understand your design at the [Physics Constraints](/physics-constraints/overview.md) level so that design parameters, such as Net Widths, can be independently managed on a constraint-by-constraint basis by Quilter, as opposed to using traditional design rules that can be overly conservative and cumbersome to define.
That said, Quilter supports a "Net Widths" constraint that can be used to specify specific trace widths for individual nets and net classes within your design.
If you want to assert custom [Fabricator constraints](/using-quilter/fabricator-constraints.md) for your design, we recommend waiting until our support for custom stack-ups and design rules is complete.
{% hint style="warning" %}
**Use Net Widths Carefully**\
We don't recommend using the "Net Widths" constraint for global enforcement of fabrication rules. Net widths can "collide" with other physics constraints that automatically manage net widths and spacing, including [Power Nets](/physics-constraints/power-nets.md). We recommend using this constraint sparingly.
{% endhint %}
### How to specify
To specify a preserved pour, add the specific net or net class to the "Net Widths" constraint during Circuit Comprehension by clicking the `Add`, `Add multiple`, or `Add by netclass` buttons beneath the table.
Add by net
Add by net class
---
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