A method is provided for generating real-time haptic response information for a haptic simulating device during a surgery simulation performed on an object volume by a virtual tool that is associated with the haptic simulating device. The object volume includes tissue voxels, null voxels, and object boundary points located between corresponding adjacent pairs of the tissue and null voxels. The method includes: (a) obtaining a current center position of the virtual tool; (b) determining a current tool subvolume of the object volume; and (c) upon determining that the current tool subvolume has at least one tissue voxel, performing the sub-steps of: (c-1) determining positions of tool boundary points within the current tool subvolume, (c-2) updating labeling of the voxels within the current tool subvolume and replacing an original set of the object boundary points within the current tool subvolume with a new set of the object boundary points, and (c-3) providing force information of a force to be generated by the haptic simulating device.