An apparatus includes at least one processor configured to execute a plurality of tasks including a first normal acquiring task configured to acquire first normal information of an object, a designated area acquiring task configured to acquire a designated portion in the object, the designated area being designated by a user, a second normal acquiring task configured to acquire second normal information of the object, the second normal information being normal information having a lower frequency than a frequency of the first normal information, a virtual light source determining task configured to determine a virtual light source condition based on the second normal information corresponding to the designated portion, and a rendering task configured to generate a rendering image using the first normal information and the virtual light source condition.