How to counter error in blueprints while using them?
Actually these are not errors but sometimes curve don't coincide and then i can't patch that surface.
if your project curves do not end up coincident, do this
1. go back to the sketches used to create the curve
2. if possible convert the edge or curve you want it to be coincident to
3. add a coincident relation between the converted edge/curve or edge/curve and the endpoint of the line in ur sketch
4. do this for all sketches that make up the project curve [ensure that both sketches have the same endpoints]
This should solve the problem