Assets from Daz Studio are usually awesome, but they often have a high polygon count. This can give problems with performance, especially if you like me use an old Win 7 box from 2009 with only six gigs of ram. Often it is possible to reduce the polygon count with little effect on the final renders.
This is where the Low-poly Versions section at the bottom of the Setup panel comes in. In the unstable version it looks like this
Here is the original character, weighting in
Verts: 21556, Edges: 42599, Faces: 21098
Verts: 7554, Edges: 17800, Faces: 10311
i.e. the number of vertices is almost reduced to a third.
However, there are a number of problems, e.g. the black spots in the should areas. The quick low-poly uses Blender's Decimate modifier, which does not respect UV seams. A decimated face can contain vertices in different UV islands, making the middle of the face stretch over random parts of the texture.
Moreover, since the quick low-poly applies a modifier, the mesh must not have any shapekeys. This is not such a big problem for Genesis 3, where facial expressions are implemented with bones, but for Genesis and Genesis 2 this means no face expressions. The Apply Morphs button is duplicated in this section to get rid of any shapekeys before making a quick low-poly.
The footprint of the faithful low-poly is
Verts: 11885, Edges: 21136, Faces: 9306
This is slightly higher than the quick low-poly, but still a nice reduction.
There are still some problems. In the illustration the shoulders become very jagged when posed. This can be fixed by adding a Subdivision Surface modifier. If the number of view subdivisions is set to zero, the viewport performance should not suffer too much.
After triangulating n-gons the character weighs
Verts: 11885, Edges: 31111, Faces: 19281
The number of edges and faces has gone up considerably, but I'm not sure that this affects performance, since complicated n-gons have been replaced by simple triangles. The number of vertices stays the same, which is what I think is most important for performance.
Verts: 123506, Edges: 240687, Faces: 117264
Reducing the weight of a 21,000 verts character makes little sense if we leave her with 123,000 verts worth of hair.
Verts: 32574, Edges: 61862, Faces: 29370
without any notable reduction of quality.
A second iteration of the Faithful Low-poly button reduces the hair further
Verts: 9281, Edges: 16743, Faces: 7544
Compared to the original 123,000 verts, the footprint has gone down with more than a factor of ten!
We now start to see some bald spots on the head, but it should not be too difficult to fix them in edit mode.
Verts: 10081, Edges: 20047, Faces: 10048
The baldness problem is perhaps a little less pronounced, but some manual editing is still needed.
Verts: 114074, Edges: 167685, Faces: 55553
We don't want the skull cap to be selected, so we hide it (select one vertex on the skull, use ctrl-L to select connected vertices, and H to hide).
Verts: 56116, Edges: 82748, Faces: 27574