This document discusses, among other things, systems and methods for delivering electrostimulation to specific tissue of a patient. An example of a system can receive a three-dimensional voxelized model representing a plurality of regions each specified as a target region or an avoidance region. The system includes control circuitry to determine a metric value using the voxelized model. The metric value indicates a clinical effect of electrostimulation on the plurality of regions according to a stimulation current and a current fractionalization. The control circuitry can determine a desired stimulation current that results in a first metric value satisfying a clinical effect condition. The system can generate a stimulation configuration including the desired stimulation current and the current fractionalization corresponding to the first metric value, and deliver tissue stimulation according to the stimulation configuration.