problem in the sketch with turn offset

[ijk]

Hello everyone,
I just started seeing solidworks and I have a trivial problem with an offset of a curve converted from 3d geometry in the sketch.
I attach images to make the matter understand (all is only for exercise purposes).
I want to perform an offset of the converted curve to get the contour of an emptying (the latter I will then perform it with extruded cut) as you can see in img00 and img01.
after cutting the offset curve from the surplus parts (img02) I try to change the value of the 60mm quota, bringing it to 30mm I obtain the result in img03 (so far ok).
changing the value of the 30mm share start the problems: the right vertical segment turns red img04 (I don’t know why and also diagnostics does not work). immetto the 50mm value, confirm and sketch remains with the red segment and does not update img05.
I go out of the sketch and return and everything regenerates with the unexpected result in img06.
I can't figure out what's wrong.

 

[MassiVonWeizen]

if it is only for exercise it would also be useful to attach the file to understand where the error is. insert software and version in profile
I've been flying back, and it's no problem.
procedure I did:
-offset of curve
-designed a rectangle that intersects the curve
-cut all surplus lines with the command shortens the entities
-quota as missing

Note well: you do not need to convert the curve to make the offset, just select the entity of the solid. if you convert it equally you have to set it as a building entity

 

[ijk]

Hello Masses,
I tried to directly offset the curve from the solid and I actually don't match any problems.
I had previously used the conversion of 3d geometry by selecting the curve from the solid and then made the offset of the converted curve.
attached there is the file.View attachment Prova offset curva convertita.7zThanks for the help.

 

[MassiVonWeizen]

seems to depend on the offset spline, or rather from its reprocessing after moving; if you close the sketch and reopen the error disappears and if you change the odds without entering the sketch all smooth row. said this, was it necessary a spline to make that curved cut?
apart from this:
first sketch: it is underdefinite. cases where the underdefinite sketch is acceptable are very few; a parametric cad needs well-made sketches, with logic and completely manageable.
Second sketch: As already mentioned, you do not need to make a convert entity, the offset is also done directly by geometry. more entities there are in a sketch more things to control there are and the greater the risk of falling into errors (and by this I mean that with the continuation of modeling each modification/cancellation of entities can create disasters)

 

[ijk]

Hello Masses,
Thanks for the advice.
the file I uploaded is an exercise whose only purpose is to know and test the functions of sw.
Do you ask me if you need a ball for the curved cut? for what I just said I'd tell you: "certainly, it's not just an exercise." However, if an entity designed in a cad has a geometric sense (and the spline drawn to the contrary has it) a good cad must be able to manage that entity without causing problems to the user.
the first sketch is underdefinite and certainly it is good to define sketches, but also to define the problem in the second sketch remains.
in the second sketch as you have emphasized it is not necessary to use the curve convert, but I can do directly the outset of the edge taken on 3d geometry and the problem disappears.
I want to emphasize a detail that I noticed. It would seem that when I use the curved convert, sw does not maintain the original nature of the curve, i.e. spline type (as should) but transforms that curve into a parable defining its fire and summit (perhaps the spline obtained with 3 points are parables: you should investigate the spline theory). After the offset, I find myself the offset of a parable. This does not happen if I execute the edge offset taken on 3d geometry: In this case I have the offset of a spline.
I tried to add another control point to the spline of the first sketch by turning it into a curve very distinct from a parable, thus allowing the convert curve to maintain the initial nature of the curve (spline was and spline remains) and actually the problem in this case is not even doing the offset of the converted curve.
Obviously, the offset of the parable has problems of geometric nature when I impose the quota to the values for which I have found the difficulties highlighted.