why generaly we are not using 3d sketch or position sketch in catia (or)solidworks???
some one ask this question me in interview but i dont know the reason. can any one answer this question?? where we use 3d sketch option??
CATIA sketches are only 2D.
Solidworks sketches can be 2D or 3D sketches.
I use 3D sketches with weldment creation. A machine frame can be drawn, joints specified, and cut list in a fairly simple process. I have also used wood profiles I created to create building framework.
2D sketches are easier.
The only time a 3D sketch is used is when a 2D sketch does not do what you need. Even then it is possible to use a tool like Project Curve which gives a 3D result from two 2D sketches.
If I had to draw a cube in a 3D sketch, I would not be using CAD software. Drawing a 2D square, then extruding it for the third dimension is much easier, and faster.
When I make an exploded assembly drawing in SolidWorks, the Exploded Line Sketch is a 3D sketch.