A computer is caused to execute processing that that determines, based on a first usage amount of a hardware resource which is allocated for processing corresponding to objects of a first category including an essential object located in a target scene, a second usage amount of the hardware resource that is able to be allocated for processing for objects of a second category different to the first category. Also, the computer is caused to execute processing of deciding, for objects of the second category which are located in the target scene, types of those objects and an outer appearance parameter for each type based on the second usage amount and information for deciding outer appearances for when the objects of the second category are located in the target scene.