How to draw editable 3d sketch in fusion 360

Anybody had succesfull attempts on 3d sketches in fusion 360? Im here wondering if its just lack of my skills or am i asking too complicated tricks form the program again..

The problem is my sketch somehow goes in uneditable state when i draw reasonably simple 3d path to later swipe a tubular pipe frame along it.
And by uneditable i mean i cant later edit the dimensions even though i have constrained the sketch the way it has enough freedom to do what im asking. Sometimes i can edit some of the measurements few times and then it gets stuck.

It just gives me "Error: Failed to solve.
Please delete or modify one of the following constraints/dimensions"

If 3d sketching is dead end for parts like this then how do you recommend creating shapes like this to be easily editable?

My model im talking about is there:

Ignore the seat, and all the credits for that to the original creator: Seat Mount

Attached the fusion part also if someone wants to experience the problem

1 Answer

Eventually i managed to make it work. Seems like the problem is something weird that happens when i add sketch fillets to the model. Some constraints disapear in the process, but somehow they are still there. And if i then add more constraints to fully constrain my model it just locks.

So i'm now convinced there is indeed a problem in 3d sketching. Model can be never fully constrained and even then it might lock itself when i change same dimensions too many times.
Just in case someone else is wondering what the heck they are doing wrong for days. So nothing it's just broken..