Voxel from a series of 2D slices (r.to.rast3), interpolated from 3D vector points (v.vol.rst).
Interpolation of 3D vector points
Regularized spline with tension method is used in the interpolation. The tension parameter controls the distance over which each given point influences the resulting volume (with very high tension, each point influences only its close neighborhood and the volume goes rapidly to trend between the points). Higher values of tension parameter reduce the overshoots that can appear in volumes with rapid change of gradient.
v.vol.rst --overwrite --verbose input=bull_point@marathousa wcolumn=z dmin=0.25 elevation=bull_surf
v.to.rast3 --verbose input=geo_point@marathousa output=geo_voxel column=z