sketch errors. over constraining and redundant - beginner help

rlbrk

Where can I find good explanations about over constraining and redundant? I cant get my sketch fully defined with dimensions without errors, when I success at fixing one error, right after I got another error, I need to learn how its working exactly. 
For example, how do I change the yellow dimension without getting an error? should I need to change both 6.4 dimensions for it to work? its really confusing 

Ste_Wilson

You don't need the yellow dimension as, I'm guessing that you have a symmetrical constraint and your mid point of the yellow dimension is in line with the origin so the 96 is defined by the 21.1 and the 26.5 dimensions.

Can I suggest doing the Onshape self paced courses?

https://learn.onshape.com/courses/fundamentals-sketching

Just a quick way to do it differently.

Mostly defined around the centre. No more dims required.

rlbrk

I did the sketch and fundamental courses. what should I do know? where can I continue practicing? maybe you have some recommendation on a good youtube videos? 

Ste_Wilson

http://www.pearltrees.com/stephenteacher/onshape-cad-getting-started/id69657740

A few links

The cad video tutor linked above has some good YouTube tutorials.

rick_randall

harel_barak952 , Good advice above, and I would add.

To obtain speed and efficiency while sketching you should always ask yourself if your part has symmetry. If it is a round part - only draw half of the profile, then revolve (this saves time while sketching and placing dimensions)  If you are working on a specific tutorial, then this advice may not apply. But it is still good practice to follow this rule on your other work.

 If you are looking for practice, I would suggest taking a project you have done before, and starting from scratch, do it again - trying to reduce the number of steps, or eliminate some complexity from sketches. In other words, completing it faster. Discovering ways to speed-up your modeling technique usually gives a "best practice" type scenario.

Keep at it, and good luck.