Cura, like many slicers, allows one to set the number of passes for top, bottom and sides. By setting these values to zero, your model becomes completely and only infill. The pattern selection for infill allows you to choose the design which would appeal to you and possibly match that of the raft.
I've just now imported a mostly monolithic STL file and tested the above. By varying the percentage of infill, various patterns result. Low infill percentage values make for a mostly empty print, while the higher numbers provide attractive geometric results.
Of course, one would want the original model to have sufficient wall thickness to create the objective.