Can I change my project's framework?

No. The framework is chosen when the project is created, and it cannot be changed afterwards. There is no setting that converts a Bootstrap project to Foundation, or a Materialize project to frameworkless.

Why it works this way

A framework is not a setting laid over your design — it is the design’s vocabulary. Every framework ships its own class names, its own grid, and its own JavaScript, and none of it transfers:

• The class names are framework-specific. Bootstrap’s col-md-6 means nothing to Foundation. Foundation’s grid-x means nothing to Bootstrap. Swap the stylesheet and every element styled with those classes loses its layout at once.
• Elements and components are not interchangeable. A Foundation Orbit gallery and a Bootstrap carousel are different markup driven by different scripts. There is no equivalence table that turns one into the other.
• The workflow direction differs. Foundation, Bootstrap and Materialize are mobile-first; frameworkless can be desktop-down. Your breakpoints were authored in one direction and would not read correctly in the other.

Converting a project would mean rewriting the class names, the components and the breakpoints — in other words, rebuilding it.

What to do instead

Create a new project with the framework you want, then bring across what actually travels.

What carries over cleanly

• Content — your text and copy.
• Images and files — re-import them through the Resources dialog.
• Your own custom classes — class names you invented are yours. The names come across; the layout rules built on framework classes do not.
• Structure as a reference — keep the old project open alongside the new one and rebuild against it.

What does not

• Framework grid classes and any layout built on them.
• Framework components: modals, accordions, carousels, off-canvas menus, orbits.
• Framework-specific breakpoints, which differ between the three.

If you are early in the project

If you have only built a page or two, starting over in the right framework costs an afternoon. If you are twenty pages in, budget properly for the rebuild — and consider whether the current framework is genuinely blocking you, or whether it is just not the one you would pick today.

A framework you know well and did not choose is usually less trouble than a rebuild.