Greetings,

This problem is eating me a lot of time and giving me a lot a frustrations.

Very often, the 3D sketch I'm working on is going haywire like this for no apparent reason:

(and it can be way worse sometimes)

The shape I'm going for usualy looks like this:

It can happen or not, sometimes, it's ok and sometimes it's not with the same conditions.

It can happen when I'm draging a point or adding a constraint.

It feels like SW 3D sketch code is not very well tuned or I'm not working properly, I don't know...

Also, I can have another problem which gives me headaches (sory for the double question, but it is kind of the same issue). Sometimes, when I'm adding a constraint, even if the sketch is not completely and over-constrainted, I got a red and yellow devil:

I let the assembly I'm working on attached for you to play with, please note I'm working with the routing add-in with custom made components, ("Y-dusting intersection 45° unflanged - Ø24", "dusting-flange" and "dusting pipe unflanged") included in the pack-and-go document, you may have to repair some links since routing can be temperamental.

You can try to constraint the far left bottom segment to 2 inches (which should not be over constrainted if you do) and you should get the red and yellow devil

Thank you in advance for any help!