Having problems with projected geometry

[DaveGadgeteer]

(Inventor 2014) I often project some geometry into a new sketch. Generally I want to trace over part of it and add some lines to define a new profile.

Almost every time, I get terrible problems as a result, and I'm wondering what I might be doing wrong.

The trouble seems to be that the lines I draw get entangled with (constrained to and perhaps connected to) the projected yellow lines in strange ways. The problem always shows up when I go to close the loop. I'll work my way around the lines closing, then I'll hit an error message like "need to have a coincidence constraint here", and when I tell it to go ahead, it will say "adding a constraint will over constrain the drawing", so it doesn't happen, and the loop can't be closed. The software is in a strange mode, too, not adding lines to close but not being in true edit mode either. I need to hit escape to make things work again.

Usually it's impossible to get past this error, and the fastest way I've found to go on is to delete all the lines I've drawn and draw them somewhere else, close the loop there, then constrain them back into the right place relative to the projected geometry This seems like a big waste of time, it can't be normal procedure. Frequently the loop has broken by the time I have everything in position again, and once again I may have troubles closing it. Loops seem extremely fragile.

I looked up projecting geometry in a thick Inventor book, and it seems to imply that one must finish the sketch after projecting and before adding lines. But I don't notice any difference.

What are the yellow projected lines? I assume they're like guide lines, construction geometry, but sometimes they must act like lines I've drawn except that they can't be moved or deleted.

Another related problem I have is that sometimes I project a wrong line, and when I discover that error, there's no way (too late to undo) to delete the wrong projected geometry. How does one do that?

[JDMather]

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@DaveGadgeteer wrote:

I looked up projecting geometry in a thick Inventor book, and it seems to imply that one must finish the sketch after projecting and before adding lines. But I don't notice any difference.

Another related problem I have is that sometimes I project a wrong line, and when I discover that error, there's no way (too late to undo) to delete the wrong projected geometry. How does one do that?

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Attach your file here, it sounds like you are not sketching with the best techniques.

I don't think you are following the book correctly (and thick Inventor books usually have names and authors for reference).

If you project the wrong line, then simply delete the projected geometry.

I recommend you go through these

http://home.pct.edu/~jmather/SkillsUSA%20University.pdf
http://inventortrenches.blogspot.com/p/inventor-tutorials.html
http://wikihelp.autodesk.com/enu?adskContextId=HELP_TUTORIALS&language=ENU&release=2014&product=Inve...