1. A computer-implemented method to identify a manufacturing problem area in a layout, the method comprising: performing, by computer, a model-based simulation for a first sample in the layout to obtain a first simulation-result which indicates whether a feature associated with the first sample in the layout is expected to have manufacturing problems; associating, in a database, the first sample with the first simulation-result; and in response to determining that a rotated version of a second sample in the layout is substantially similar to the first sample in the layout, using the first simulation-result to determine whether a feature associated with the second sample in the layout is expected to have manufacturing problems.