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Supports - Out of places !  

New Member
Supports - Out of places !


Finally able to try out Prusaslicer and its wonderful paint on supports & seam alignement features. It's really great !

Coming from S3D I'm used to having near perfect supports. And that's the only reason why I keep it around for now. The problem I get with PS speaks for itself as you'll see in attached pictures.

Model is from

Supports are expanding way too much outside of the model even though I placed them with 1mm brush and only at minimal places.
I need them to be at 45° so they go evenly on all 3 sides so changing the orientation isn't an option, and even though, it keeps expanding way too much.
In S3D there is an option called "inflation distance" allowing the supports to expand more outside their designated zone. Would there be a similar setting f*cking things up and causing this ?
Right now the picture I provided shows very minimal supports. If autosupport is used it's even worse as they are fused to the model at multiple places, preventing them from being removed.

Thanks for any advices you can provide 🙂

Posted : 19/03/2021 7:33 am
Famed Member
RE: Supports - Out of places !

That's currently under development for 2.4.  From the posts on Github it looks like they are revamping supports  in a major way.  Supports looks at the surface that needs support and then expands out from there to what it thinks it needs.  Its always been very aggressive.  So can go out rather majorly.  I get the impression that 2.4 isnt that far away either from a release, at least a pre-release to play with so signing up for github notifications on the prusa slicer project might be handy.

Also curious as to why are you painting an enforcer on the bottom of the weaver rail sections ?  Normally you paint the surface that needs supporting and not the area at the bottom of the support, none of those blue areas actually need support when printed in that orientation. 

Personally when I design weaver/picatinny rails I slope those sections in the cad design.  While they are then not quite to 'spec' they work still and print without any supports.

For supports in general as they are now, if you are having difficultly removing them its probably because the default settings suck.  At a minimum you need to set the contact z distance to 0.2 or 0.25 for a 0.2mm layer height.  The default of 0.1 will weld the supports to the material.  For those I'd actually try reducing the spacing down too.  Setting interface layers to 4-5 can also help removal.  I've found that sometimes if the spacing is smaller (like 0.5-1mm) it can reduce the amount of expansion as it can fit more support into the smaller area.  I'm not sure if that will work in this case though as those grooves are rather small.

If you save your project (File>Save As) to save a 3mf file and then zip it into an archive and attach it then we can play around with the settings and see what we can get.  Must be zipped or the forum doesn't accept the file types.  

Posted : 19/03/2021 11:25 am
New Member
Topic starter answered:
RE: Supports - Out of places !


Hey, thanks for your reply ! For the RIS I didn't model it so having to rework it is a hassle without a step file 🙂

I figured the supports were way too aggressive, let's hope 2.4 fixes that. Also, I modified the settings for better removal already but no luck on that, mainly because they are expanding too far and "sticking" to the model 😉 

Now, as for the support placement to be honest painting it like that or having PS setting them automatically results in the same problem, but thanks I didn't think about only adding it to the top part !

Posted : 19/03/2021 11:38 am
Noble Member
RE: Supports - Out of places !

This is for me perhaps the most vexing aspect of PS at the moment. The supports it lays down are just crazy aggressive. Glad to hear that they’re trying to tackle it in 2.4. Paint-on support was a great addition, ways to rein in support to something more reasonable would make it perfect.

Posted : 19/03/2021 11:58 am