Mid-Align Constraint (in-between faces)

[m_gasztych]

This would let you select a pair of faces on one component and a matching pair on another, and have Inventor constrain centre/align both components. It's especially useful when working with components that have a clearance or interference fit, but really it applies to any components that need to be centred to each other.

This functionality already exists, to some extent, within Inventor's joint relationships. However, as proven by the number of questions on the Inventor forums asking how to constrain components this way, it clearly isn't easily available or intuitive for quick, simple constraining. Joints are powerful and offer plenty of options, but using something like an "in-between faces" planar joint to centre two components quickly becomes a complex process. It has its own quirks - it moves components, strips grounding from grounded components, and requires a specific order of face selection and origin definition. It's also prone to user error along the way, taking upwards of 12 mouse clicks just to set up.

A similar result can be achieved by constraining origin centre planes, but only if the component is symmetrical and the planes are in the right place - which very often isn't the case, especially with imported STEP files.

I believe we need a dedicated constraint purely for this scenario - one that simply asks the user to select two faces on one component and two faces on another, then constrains them at the mid-distance between both selections.

Ideally this wouldn't be limited to a single pair of mating components either. At assembly and sub-assembly level, it would be just as useful to centre one component between faces belonging to multiple other components, rather than being restricted to one matching part.

A demo of this constraint type in action can be seen in the videos below.

The demo above shows an iLogic "Mid-Align" constraint I built using the existing "in-between two faces" planar joint definition via the iLogic API, simplifying the user's input down to just four face selections and adding some extra logic to handle the definitions automatically. Full code can be found in this topic: Solved: Re: How to get a non-circular part (square or other) into center of a non-circular hole. - P...

I believe having this built natively into Inventor's Place Constraint / Assembly Constrain command would be a huge workflow improvement for a lot of scenarios, and would quickly become one of the most commonly used constraints - improving Inventor's overall ease of use and constraining intuitiveness.

Thanks!

[MattH_Work]

Not being negative towards your code ( looks pretty good ), but this exposes an issue with the Joint command itself.

The lack of 'between 2 faces' when working with 2 components ( between 2 faces ONLY works with faces on the same component ) means we cannot use your code to connect a component 'centred' to an Assembly

This 'feels' a simple change Autodesk could make ( I know, it may be 10 lines of code, it could also be 10, 000 lines of code )

[m_gasztych]

You're right, that is a limitation of the joint relationship as it stands. Going further with this, we'd obviously want the ability to do this at assembly/sub-assembly level too - constraining one component centred between faces on multiple other components, not just a single mating part.
Good spot, actually - I meant to include this in the original post and completely forgot. I'll edit it in.

[viarosenco7RUE2]

I come from SW background and I miss a lot Inventor analogue to their "Width" mate. Creating and mating Work planes on both components feels a bit of extra work.

[m_gasztych]

I agree, and in a lot of cases adding or editing work planes on both components isn't simple, or even possible - for example, with third-party imported 3D models, or locked files in Vault that you wouldn't necessarily want to edit.

[WCrihfield]

Even when trying to use the Symmetric constraint (which I use a lot), it will not let us choose two Faces/Planes belonging to the same component or sub assembly.  This is HORIBLE functionality.  Like you said, we can not always create a 'center plane' in the component we want to constrain, so using its existing Faces & Planes are our only option, but then Inventor does not have an 'option' for that in its assembly constraints, without having to do a bunch of extra work and steps that should not be necessary.