Modeling
Polygon fundamentals
A polygon mesh is vertices, edges, and faces. A candidate must know manifold versus non-manifold geometry, normals, and face winding. Reversed normals cause dark shading and failed booleans. Mesh Display > Reverse flips normals; Conform makes them consistent.
Construction history
Most modeling tools are history nodes (for example, extrude, bevel, boolean). Editing the input mesh updates the result. Deleting history bakes the current shape, which is why a question about a bevel that no longer responds to its input mesh usually points to deleted history.
Core tools and their traps
- Extrude offsets faces along normals; Keep Faces Together controls whether a region extrudes as one shell or separates.
- Bevel rounds edges; Offset Type (fraction, absolute, world) changes how width is interpreted.
- Multi-Cut inserts edge loops; snapping to a percentage along an edge is a common exam detail.
- Booleans (union, difference, intersection) require manifold, closed geometry to behave predictably.
- Smooth Mesh Preview (pressing 3) is display-only; it does not change the base cage unless you convert.
- Combine merges objects into one mesh but does not weld overlapping vertices; Merge Vertex Tool and Merge Threshold do.
Rule of thumb
For clean deformation and subdivision, keep quads, avoid n-gons on curved surfaces, and place edge loops to support the shape.
Worked example
A bevel looks faceted after smoothing. The bevel node's Segments is 1, giving a single chamfer. Raising segments to 3 or more, or using the bevel node's Miter and Offset settings, produces a rounded result. Note the trap: increasing Smooth Mesh Preview does not fix a low-segment bevel because preview subdivides the cage, not the bevel's own profile.