I have a sculpture with 250,000 vertices and I select the head (70,000 vertices) I would like to rotate the head 12 degrees around the z axis with proportional editing enabled so the neck and upper torso twist with it, when I do this Blender crashes on my computer. Is there any way around this problem? One way that seems to work is to deselect 95% of the vertices on the head, the trouble is I only know how to do this one vertice at a time!
It would probably be better to use a lattice modifier but if you wish to deselect vertices the following method seems to work for this example. Select the area you wish to manipulate then go to the 3D viewport header choose: Select > Random, go to the bottom of the tool shelf: enter Percent> 99% (for example) and Action> Deselect.You may need to add a few vertices to fill in any gaps. You can now manipulate using the proportional editing tool set to a largeish fall off without unwelcome lag or crashes.