You can optimize hide situations to improve performance.
Hide situations created with AMSHIDE update dynamically. Every time you move an object in model space, the program recalculates hide situations. If a drawing contains complex hide situations or an unusually large number of hide situations, you may notice a degrading of performance. AutoCAD Mechanical provides two ways to work around this problem.
When you suppress a hide situation, AutoCAD Mechanical does not calculate the hide situation. As a result, objects that are obscured by other objects are not shown as hidden. The mechanical browser indicates suppressed hide situations by dimming the hide icon. You can suppress all hide situations, the hide situations of a particular assembly only, or the hide situations of an individual part or folder. Right-click the node in the mechanical browser and select the appropriate Suppress menu option. You can unsuppress the hide situations at any time.
This option is available under Object Settings in the Edit Hide Situation dialog box. (Double-click a hide situation in the mechanical browser to open the dialog box.) When you enable this option, the program saves the outer contour of the foreground for use in subsequent hidden line calculations. If you modify the foreground, hidden lines may not calculate properly because the program uses the saved outer contour for the calculation, not the actual contour. At any time, you can turn off this option and recalculate hide situations using the actual foreground shape contours. The other disadvantage of this method is that you must enable the Use Outer Contour Only option before you can save the outer contour. If the foreground object has through holes, through which the background objects must be visible, you cannot use this option. The advantage this method has over the suppress method is that hide situations continue to appear in model space.