To Decimate Facets
The Decimate command enables you to reduce the number of triangles without compromising the surface integrity or detail.
1. Click > 
Decimate. The Decimate dialog box opens.
Decimate. The Decimate dialog box opens.2. In the Percentage To Keep box, type a value for the percentage of original points that you want to retain.
3. To fix the boundary of decimated facets in relation to the surrounding facets after decimation, select the Fix Boundary check box. This is useful when the boundary consists of corners or feature lines that you want to retain.
4. Click OK.