Inventor doesn't update user parameter if change is smaller than ~1e-7 mm

[Georgie-G96]

I'm working in Inventor 2026 and noticed that if I try to change a user parameter from 6.00000001 to 6, Inventor doesn't update the value — it keeps showing the original.
This happens even when the difference is as big as 0.00000001 mm.

I confirmed there's no equation, no Excel link, and no iLogic rule interfering.

Shouldn't Inventor treat this as a valid change?

[swalton]

I think you are running into the limits of Inventor's modeling precision.  1 e-7 mm is 1 e-10 m, if I moved the decimal correctly.

Per the help file, Inventor assumes any difference smaller than 1e-8 m is 0.  It seems that that Inventor is not able to see the difference in size.  There may be a display bug for the last digit.  See: https://www.autodesk.com/support/technical/article/caas/sfdcarticles/sfdcarticles/Inventor-Part-size...

Or maybe it is related to the display issue here: https://forums.autodesk.com/t5/inventor-forum/inventor-2024-parameter-precision-issue/td-p/11906159 

[johnsonshiue]

Hi! The behavior does not look right to me. It should honor the value change or at least 8 decimal places. I will work with the project team to understand it better.

Many thanks!

[johnsonshiue]

Hi! I vaguely remember seeing the issue before. Indeed, it was reported as INVGEN-83817. It is a legacy behavior, which can be reproduced previously. Unfortunately, it has not been fixed yet.

Many thanks!