can mechanical engineer be car designer
You can!!!! but Designer sounds raw, bcoz there are different different types of designing from the free hand sketching (not modelling using software) till the Modelling part done in CAD and Autodesk products for automobiles.
Yes autodesk Alias, one of the best in class and developing software for Surfacing ( class A), part of a styling too.
SO what ever may be your case, be very clear about what you want.