While its great to have the "disable" function in the context menu (A2plus was missing that), the hard thing is to find out which ones are the redundant constraints. The last one added might not be the cause of the failure. I tried the AssemblyObject/Properties/Verbose=true but I was not yet able to understand which bits from the several pages of information in the report view I need to find the faulty parts.

So I thought instread of uploading large files with linked assemblies, maybe its helpful to discuss about how to constraint simple situations so that redundant constraints are avoided.

For example, how to constrain two parts made to be attached to each other with srews?

The image below is a simple case that yields the error "inconsistent constraints", at least after misaligning the parts. I think the problem is about DegreesOfFreedom (DOF). We need to get from 6 to 0 to be fully constraint, but not below 0. Also we should constrain each axis once, and only once. That requires a good understanding about which DOF each constraint removes.

So above we have

- Axis alignment, leaving 2 DOF. It takes all but axis rotation and axis movement

- PlaneCoincident, leaving 1DOF, it takes all but axis rotation

The PlaneCoincident constrains offer the property "lock angle" which takes all 6 DOF, but in the case above we do not have a reference for 0°. There is not simple way to define that, so a proper constaint set for this case is not trivial.

Another solution might be to align one axis and the the bottom faces. This does not work, because the two parts are not straight, so the holes would not align when the two bottom faces would be aligned. But even in cases where this is not a problem there are still have redundant constraints, so this

- Axis alignment, leaving 2 DOF. It takes all but axis rotation and axis movement

- PlaneAlignment,leaving 3 DOF, it takes away axis translation and both non-axis rotations.

What I found to work is

- Axis alignment, leaving 2 DOF. It takes all but axis rotation and axis movement

- PointsDistance, leaving 5 DOF, it works in spherical space and takes away radial distance and axis translation and both non-axis rotations.

*Working attachment with 2 hole aligned without redundant constraints (hopefully). This file is attached.*

I am not sure about the best solution, but from this exmple I think that to master Assembly3 its a required step to learn which DOFs each constraint takes away (not only how many). As its not very intuitive to think about that for each constraint step, I guess its quite helpful to to come up with some optimized solutions for the current Assembly3 solver for standard situations like

- align at one corner and faces

- mount on a suface aligning faces

- attaching a srew

- align a part at two hole

- mount axial aligning one face

- mount axial aligning a radial (line)

etc.

This is the file with the last solution