Set TransparencyKeyCreator \ Tools \ Face-Tools \ Set-Transparency
Location: Tools>Customize>Main Toolbar and listed in Commands>Tools>Face Tools
This function can be used to apply a transparency value to any solid or surface. By default the faces will be highlighted, use the toggle selection to choose the solid. The value you specify for transparency is a percentage of full transparency. The function used to be called up in Tools>Face Tools but is being phased out by the Part Splitter Material tab and in Edit>Entities>Set Material Properties.
Specify a transparency percentage value. Decide whether to apply the transparency value to individual faces or entire bodies.
Above> Transparency applied to spheres at 10%, 40%, and 70%.