topic Variable dimensions for tolerance?/How best to incorporate tolerances in a sketch? in Inventor Forum

Variable dimensions for tolerance?/How best to incorporate tolerances in a sketch?

Neo-CAD — Tue, 30 Sep 2025 17:15:37 GMT

(I am a student who does a fair bit of 3d printing- This is my second (?) year using Inventor)

Currently, the way I've been doing tolerance is by adding or using a previous dimension. I've also recently been renaming these dimensions to find them easier. (T1, T2, etc.)
So, I might first define the tolerance for a tight fit (T1),

and then use it in later dimensions, like doing an offset of a hole for a matching peg. (T1/2)

This lets me adjust the original dimension to change the tolerances on everything later, which is useful if I need to print with a plastic with different tolerances.

This works fine, but I'm wondering if Inventor offers support for actual variables in dimensions.
Rather than relying on previous dimensions, can I create variables to use before hand?

Or rather- How do you/how would you go about incorporating tolerances that can be adjusted later?

Re: Variable dimensions for tolerance?/How best to incorporate tolerances in a sketch?

dan_inv09 — Tue, 30 Sep 2025 17:34:32 GMT

Do you just want to create user parameters?

Re: Variable dimensions for tolerance?/How best to incorporate tolerances in a sketch?

swalton — Tue, 30 Sep 2025 18:00:24 GMT

I typically model the dimension at nominal size, then edit the dimension to add specific tolerance info.

These types of tolerances are typically used to define the allowable variation from the as-designed dimension value.

In your case, it may be a better approach to leverage Model States. The general workflow would be something like this:

Model the part with dimensions and tolerances appropriate for 6061t6 aluminum made on a 3 axis CNC mill.
Create a new model state in the part, name it PLA FDM
Activate that model state.
Edit each dimension and tolerance that must change to match the material and manufacturing method.
Add more model states as required to document all the different ways you intend to produce the part.
Make drawings and export files (.stl, .stp, etc) for each model state.
Send them to the appropriate manufacturing process.
Pay close attention to which model state is active when you change the design.

See https://help.autodesk.com/view/INVNTOR/2026/ENU/?guid=GUID-8E771DBE-1107-4AE8-BE3E-AF3A7977F3C6

You might try user parameters in your dimension equations.

Re: Variable dimensions for tolerance?/How best to incorporate tolerances in a sketch?

Neo-CAD — Tue, 30 Sep 2025 20:56:59 GMT

Yes, that's exactly the kinda thing I was looking for! Thanks!

Re: Variable dimensions for tolerance?/How best to incorporate tolerances in a sketch?

Neo-CAD — Tue, 30 Sep 2025 21:01:29 GMT

Parameters ended up being the thing I was looking for- but Model States sound useful, I'll have to give them a try. Thank you!