This section of the DSM Options Tab provides four pieces of information. The first is the quality of the project in terms of point mark residuals. Both the maximum and RMS residuals are given for the whole project. Beside this is an indication of whether this is acceptable or not for a good DSM result. The process of matching of image regions across images means that the photos have to be oriented to within 1 to 2 pixels. If the maximum residual is too large it will be indicated here. You may proceed with the DSM regardless but you might find the result is too noisy. The result can be so noisy as to be unusable. To get good results ensure the maximum residual is less than 2 pixels and less than 1 pixel is better.
The second piece of information is the range of base-to-height ratios of the selected photo pairs (from Photos section below). It will show the smallest to largest base-to-height ratio and an indication of what this might produce. If only one pair of photos has been chosen below then only one value is displayed. The base-to-height ratio tells us how far apart the cameras were compared to their distance from the surface. The base is the distance between the camera stations and the height is the average distance from camera station to the surface. If this ratio is too small or too large you may not get a good DSM result. A ratio of 0.2 to 1.0 is good.
The number of active DSM Trims (i.e. Trims with their enabled property set) is listed, and the ID numbers of the Surfaces that were selected when the dialog was opened are listed.