The worksphere is the 3D space in which you can work and create parts. It is like a globe around the world origin, the origin of the
global coordinate system. No portion of a part is allowed outside this worksphere.
The worksphere radius is dependent on the part resolution. When the part resolution is at the default (10e-6), the worksphere radius is 100 meters.
To change the size of the worksphere, change the geometric resolution. As the resolution accuracy is lowered (for instance, from 10e-6 to 10e-2), the worksphere gets larger (from 100 m to 1,000,000 m).
When you change the default part resolution, you can choose to set the default workplane resolution to the same value.
The minimum part resolution value you can work with is 1 micron or 0.000001 mm. Only points at this minimum or a larger distance can be handled by Creo Elements/Direct Modeling as different points.