my Ultron project part2

i have now finished my first finger assembly ,the rest of the finger was easier to make than the finger tip i guess its because i was just learning how to do surface modelling , ive been having lots of probables with a design error i came across but have fixed now called 

Zero Thickness Geometry, i have looked on Google and found this good help. 

Zero Thickness Geometry Explained

From time to time you may have received one of these error messages in SolidWorks:

• Unable to create this feature because it would result in zero-thickness geometry.
• The model could not be properly sectioned by the section line. Please check that the section line cuts through the model.

These messages will commonly occur when edges or vertices in a solid model do not properly connect with adjacent geometry. To put it simply every edge of a solid body must have exactly two adjacent faces.  Some examples of zero thickness are:

SolidWorks does not allow zero thickness geometry because it can lead to mathematical problems and downstream errors in the model.  If your unable to avoid the zero thickness design one quick way to work around this limitation is to disable the “Merge result” option of a boss/solid feature.