Methods and systems for determining information for a specimen are provided. One system includes a model configured for generating a rendered image for an alignment target on a specimen from information for a design of the alignment target. The rendered image is a simulation of images of the alignment target on the specimen generated by an imaging subsystem. The system also includes a computer subsystem configured for modifying parameter(s) of the model based on variation in parameter(s) of the imaging subsystem and/or variation in process condition(s) used to fabricate the specimen. Subsequent to the modifying, the computer subsystem is configured for 10 generating an additional rendered image for the alignment target by inputting the information for the design of the alignment target into the model and aligning the additional rendered image to an image of the alignment target generated by the imaging subsystem.