Options
This determines the scale of the Selection brush. The radius can be changed in the Viewport while holding down the mouse button.
If you own a graphics tablet, you can enable this option to make the radius dependent on the pen pressure. The Scale value defines the maximum radius, i.e., the scale when full pen pressure is applied.
Graphics tablets are recognized automatically in Cinema 4D. recommends a WACOM tablet or a tablet that conforms to the Wintab standard.
When this option is enabled you can select only polygons that are not behind other polygons. For example, if you are selecting polygons at the front of a sphere, polygons at the back of the sphere will not be selected, even if you are working in wireframe mode and can see the polygons at the back.
Another way to prevent polygons at the back from being selected is to switch on backface culling, which hides these polygons from the viewport.
In addition, you can also hide polygons to prevent them from being selected using the Hide Selected and Hide Unselected commands from the Selection menu.
Lastly, set an object's top visibility dot to red to hide that object and to prevent its elements from being selected. (You will find the visibility dots in the Object Manager, next to the object's icon.)
This option applies to edge and polygon modes. If the option is enabled, an edge or polygon will be selected if the Live Selection tool touches any part of it. If the option is disabled, the edge or polygon will only be selected once 75% or more of it has been painted.