Equal constraints confusion

[theycallmevirgo]

In the attached part, sketch "extrusion" has a horizontal line on the x axis constrained as equal to the vertical line. When I constrain the vertical line on the Y axis as equal, the inner rectangle becomes a square and shows fully constrained. Further, if I dimension  one of the mall lines, the sketch becomes fully constrained. 

From my initial understanding of the constraint system, I'm not giving any data about the dimensions of the rectangle. I want to do a simple offset. I'm not using the offset tool because I can't correctly select the target lines.  

Many thanks in advance for any assistance 

Joe

ETA I successfully used offset by turning off loop select, but I'd still like to understand what's going on. 

[kacper.suchomski]

This is because there are compatibility bonds between the square and the diagonals.

Or the diagonals lie on one straight line.

This way, if you dimension one distance edge, the system has no more mathematical solutions.

If you remove these constraints, you can still manipulate the geometry in the vertical direction.

[SBix26 · Accepted solution]

Always helpful to mention what version of Inventor you're using in the first post.  For others who may be interested, this is Inventor 2025 format.

In this sketch, you have an extra (and probably accidental) coincident constraint in the upper right corner:

This corner point is constrained to the shorter diagonal as well as the longer one, making the two lines co-linear.  If you delete that constraint, the sketch behaves as expected.

---

Sam B

Inventor Pro 2025 | Windows 11 Home 23H2