Wolfram: Opacity (Transparency)
Opacity
-
Make the surface transparent.
Opacity
is a Graphics Directivefor plotting functions e.g.
Plot3D
, you can add it by using PlotStyle
Example

ParametricPlot3D[ {Cos[u]*(2 + Cos[v]), Sin[u]*(2 + Cos[v]), Sin[v]} , {u, 0, 5}, {v, 0, 6}, SphericalRegion -> True, PlotStyle -> Directive[White, Opacity[0.7]], Lighting -> DirectionalLight[White, ImageScaled[{1, 1, 1}]], BoundaryStyle -> Directive[Blue, Thick] ]