AutoCAD 3D settings DISPSILH,SURFU,SURFV

Look at the image below. What is it? Three circles? Yes it look like that but it's not.

Running DISPSILH and setting it to 0 followed by a REGEN and the result is as follow. But is it the full truth? No.

Selecting the 3 surfaces using PROPERTIES changing U isolines and V isolines for 0 to 6

And now this is what it look like

And if DISPSILH is set back to 0 this is the result. Notice the silhouette edge of the sphere on the above image and how it is missing on the one below.

From the help file on DISPSILH (saved in the drawing):

Controls display of silhouette edges of 3D solid objects in a 2D wireframe or 3D wireframe visual style.

You can use the REGEN command to display the results.

DISPSILH also suppresses the mesh displayed when using the HIDE command in the 2D wireframe visual style.

From the help file on SURFU and SURFV (saved in the drawing):

Sets the surface density for PEDIT Smooth in the M direction and the U isolines (or V isolines) density on surface objects. Valid values are 0 through 200. Meshes are always created with a minimum surface density of 2.