To cut a 3D model in the viewport, use the clipping (or section) plane tool—standard in 3D software like Blender or Maya—for quick, non-destructive slicing.
This virtual plane lets you drag, rotate, or position it to slice through the model, revealing internal details without altering the original mesh. It’s ideal for inspecting interiors or planning edits.
For permanent cuts, later use a “split” or “slice” function to separate the model along the plane. But start with the clipping tool for fast, viewport-only adjustments.