Whats the use of Projected Sketch in Creo Parametric ?
I can not extrude the projected sketch. So whats the use of Project Command in creo Parametric ??
First of all lol, creo is frustrating like that.
if you want to extrude a projected sketch you'll have to use the tool called "offset" (Model > Editing > offset) .
select the surface/ surfaces you want to extrude on, click offset,select first box drop down to the transparent box with light blue box coming out of it (3rd option), click options and under expand area select 'sketched region', define it using the define button that pops out, this is like the sketch for your projected sketch, once you accept the closed loop sketch your surfaces should turn amber, meaning it worked,if not make sure your sketch is not outside the selected surface. Unfortunately you can extrude till certain lengths due to solving issues, and i agree with your frustration about creo.