What is a "collapsing overhang"?  

RE: What is a "collapsing overhang"?

Same question- maybe if we could hilight it in the model it would be self-evident.

RE: What is a "collapsing overhang"?

If the designer told you it is printable without supports it probably is. Slicer is complaining pretty quickly because of overhangs.

For gradual overhangs it might be a good idea to reduce layer height or at least use variable layer height and reduce height for the overhanging parts.

RE: What is a "collapsing overhang"?

@robin, thanks for your reply, but I think you misunderstand the point of my post.

Yes, the model does print without error, despite the warnings, so the designer did an excellent job.  That is not my concern.

My concern is that it's been over a month, and still no one has told me what a "collapsing" overhang actually is.  I even opened a bug report, https://github.com/prusa3d/PrusaSlicer/issues/11837, but there's been no movement on that either.

It just seems incredible to me that this warning is so poorly documented after all this time.  The PrusaSlicer wiki makes no mention of it.

RE:

From the PrusaSlicer source code:

            case SupportSpotsGenerator::SupportPointCause::FloatingExtrusion:
                if (critical) {
                     //TRN Alert when support is needed. Describes that the print has large overhang area which will print badly or not print at all.
                    message = _u8L("Collapsing overhang");
                } else {
                    //TRN Alert when support is needed. Describes extrusions that are not supported enough and come out curled or loose.
                    message = _u8L("Loose extrusions");
                }
                break;

so this is a FloatingExtrusion issue, looking further we can see this

enum class SupportPointCause { 
    LongBridge, // point generated on bridge and straight perimeter extrusion longer than the allowed length 
    FloatingBridgeAnchor, // point generated on unsupported bridge endpoint
    FloatingExtrusion, // point generated on extrusion that does not hold on its own
    SeparationFromBed, // point generated for object parts that are connected to the bed, but the area is too small and there is a risk of separation (brim may help)
    UnstableFloatingPart, // point generated for object parts not connected to the bed, holded only by the other support points (brim will not help here)
    WeakObjectPart // point generated when some part of the object is too weak to hold the upper part and may break (imagine hourglass)
    };

If you look at the picture in the first post, then we can see overhangs in blue. The problem you see is related to overhangs on the left part where they are printed on the handle parallel to the part in the middle. This way it can really be a problem.
To fix it it would be better to be printed perpendicular so that they create bridges between handle on the left and big round element in the center.