Is my project 2D, 2.5D, or 3D, and which toolpaths does each need?

The three tiers

2D: flat cutting at fixed depths. The tool moves in X/Y at a set Z, like a jigsaw or router with a fence. Cut-out profiles, pockets, drilled holes, engraved lines. Toolpaths: Profile, Pocket, Drilling, Quick Engrave. Your design is pure vectors.

2.5D: the depth VARIES as the tool moves, but it's still driven by vectors, not a model. V-carving is the flagship: the bit rises and falls continuously to follow the vector widths. Also: Fluting (tapered grooves), Prism carving, Moulding (a profile swept along a rail), Texture toolpaths. Toolpaths: V-Carve, Fluting, Prism, Moulding, Texture, Chamfer. Still no 3D model anywhere, which is why VCarve (the app) does all of it. Most "3D-looking" signs are actually 2.5D.

3D: the toolpath follows a sculpted MODEL'S surface. A component/heightmap (imported STL, purchased clipart, or Aspire-modeled) defines every Z. Toolpaths: 3D Roughing, then 3D Finishing (+ optional projected v-carves on the surface). This is the only tier where "3D clipart" applies, and the classic beginner error is trying to run Profile/Pocket/V-Carve toolpaths on a 3D clipart piece: 3D models need 3D toolpaths (the 2D toolpaths only see vectors).

Quick classifier

• Only flat bottoms and through-cuts? → 2D
• Depth varies but there's no sculpted model (pointed-bit lettering, grooves, swept profiles)? → 2.5D
• There's a model with a surface (imported or sculpted)? → 3D (Rough + Finish)
• Mixed, such as a 3D relief with v-carved text and a cut-out border? → all three, in that project's toolpath list (see the master toolpath decision guide)

Pro tips

• 2.5D delivers 90% of the "wow" at 10% of the machine time. Don't reach for 3D because a design LOOKS dimensional; v-carving probably does it.
• If you can't select it with a vector click, it's a component, and 3D rules apply.