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Support blocker not blocking  

Eminent Member
Support blocker not blocking

Alright so I have a model that needs some supports. I painted on support for the top of this hinge, and it prusaslicer (2.3.1 on mac) insists on adding supports down through the hinge. I have no need for the bottom part of the hinge (sitting on the print bed) to have supports. Supports are set for enforcers only. So I added a blocker as you see here:

and it happily puts supports right through the blocker object:

Posted : 19/10/2021 9:26 pm
Famed Member

Yes it does.  They don't work like you think they do and never have.  All enforcers and blockers do is define areas of the MODEL that need or do not need support.  So an modifier has to actually intersect the model to enforce support for an area and a blocker does the same in reverse.  A blocker does not act as an interdiction area.

Here's something else you also need to understand, once those areas are defined as needing/not needing support then the normal algorithm takes over.  As such it will place and expand support wherever the hell it thinks it needs to to support those areas where supports either through an enforcer or though the normal angle definition has been defined as 'support here'.  Even if that support goes downwards and touches the model in an area that's covered by a blocker.  You can somewhat limit the expansion by setting a lower support spacing but of t=course that results in denser support too.

Its one of the reasons that I stopped using blockers years ago and only used enforcers with the option for support enforcers only.  You can get better (though still massively imperfect) control of the supports that way.  Its even better with painted on enforcers as you can define very small areas.  As support grows out so much its better to start with a small area much smaller than you think and slice and see where the software grows the support out to.  Then slowly expand the enforcer area by painting extra bits and slicing again.

That's in 2.3.x and earlier.  The 2.4 alphas have a snug support option which is much better.  Although there are still issues at the moment with the support interface on sloped areas.  Hopefully newer alphas should sort that out as its been reported on github already.

Posted : 19/10/2021 10:28 pm