Use the Iso tool to display single iso values (iso surfaced for solids or iso line for
shells) dependent on results data.
The result data used to calculate the iso surfaces or values
can be specified independently of the result data selected in the Contour panel, even though
most of result selection options are similar to the contour options. Since an iso value is
independent of contour results, for OptiStruct design space
optimization results, you can apply a single iso surface for density, then contour stress
results on the generated iso surface. Combining contour, iso value, and transparent global
boundary geometry (shortcut key "T") is an excellent way to investigate hot spots of result
data. By varying the iso value slider bar, you can easily observe critical areas.
From the Plot tools,
click the Iso tool. Figure 1.
Figure 1. 