To minimize triangles in 3D models fast, use automated decimation tools (e.g., Blender’s Decimate modifier, Meshmixer’s Reduce command)—they quickly lower polygon count while retaining key shape details.
These tools collapse non-critical triangles, ideal for optimizing real-time models (games, AR) without manual editing. For simpler models, remove hidden geometry (like inner faces of closed objects) to cut more triangles.
For finer control, adjust decimation settings (e.g., Blender’s “Planar” mode for flat surfaces) or delete unnecessary edge loops—this balances speed with precision to avoid over-simplifying visible details.