<p>This study presents a novel and generalized method for generating collision-free and smooth tool paths in multi-axis machining. Conventional approaches often suffer from limited adaptability across different geometric discretizations and machining scenarios. To address this issue, an anisotropic heat diffusion (AHD) technique is introduced to generate smooth cutter contact (CC) curves with constrained scallop height, independent of geometric discretization types such as triangle meshes, grids, and point clouds. Considering the substantial influence of tool orientation on residual scallop height, a conservative method is developed for generating the tool orientation accessibility region. This method evaluates both global and local accessibility of tool orientations, thereby overcoming the limitations of existing accessibility analyses based solely on CC points. An optimization procedure within the tool orientation accessibility region is then employed to derive tool paths that balance safety, changeability, and machinability. Furthermore, an adaptive-order tool path smoothing method based on the Savitzky–Golay filter is developed to preserve key geometric features during smoothing. The effectiveness of the developed methods is validated through a series of case studies and comprehensive comparisons, demonstrating their applicability and advantages in multi-axis machining.</p>