Applying elephant foot compensation with a brim
 

Applying elephant foot compensation with a brim  

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WaltN
(@waltn)
New Member

After some experimentation, I have found that when you request a brim and have elephant foot compensation (EC) enabled, the brim will not connect to the model...it will have a gap of whatever the EC is set to (e.g., 0.2mm). This definitely is not what is desired, as we use a brim to help hold a part which might warp to the print bed.

It appears that PS calculates the position of the brim based upon the dimensions of the model without EC then applies the EC to the model, thus creating the gap. I believe that this is a bug.

Posted : 22/03/2021 7:37 pm
Neophyl
(@neophyl)
Famed Member

You, me and lots of other people believe its a bug.  However that is the design intent as far as the devs are concerned.  This has been brought up several times on github (where all bugs need to be reported).  For example https://github.com/prusa3d/PrusaSlicer/issues/3870  

or https://github.com/prusa3d/PrusaSlicer/issues/3915  

Their view is that if your elephants foot is causing the brim to be disconnected then you have the EF set to high.  It's one of the reasons I prefer the Super Slicer fork as that has a separate brim offset value.  So you could set elephants foot to be something crazy like 2mm and have a 0.05 brim offset and the brim will always be 0.05 from the first layer perimeters.

 

Posted : 22/03/2021 8:41 pm
fuchsr
(@fuchsr)
Prominent Member

I may be the outlier. For one, I hardly ever feel a need to use a brim, the occasional large rectangular print being the exception. And when I use it, I found the defaults to work great. Maybe there is a tiny gap but the brim seems to be doing its job just fine, and it’s easy to remove. I should say that a do prefer a bit of a squish with PLA, so maybe I’m a poster child for what the developers say on GitHub, with the EF correction offsetting the squish just so that the brim more or less abuts the part. Could/should this be an option? Maybe, but it clearly has found its way to GitHub several times already, and just speaking for myself, there’s a few other issues I’d rather have the developers look at first, such as the “bulge in the middle” issue.

Posted : 22/03/2021 11:02 pm
WaltN
(@waltn)
New Member

@neophyl

Thank you, Neophyl!  I had forgotten about GitHub…will check in there from now on. 
Please elaborate on the Super Slice fork. I’ve never heard of it. 

Posted : 22/03/2021 11:19 pm
vakil
(@vakil)
Eminent Member

@fuchsr

Got to disagree.  I do very large prints (12 - 36 hours)   and I have to tape them down because I live in an area where there are frequent power outages.  I HATE the default in PrusaSlicer that always applies it because I have to remember every time I use it to set it to zero.  I'd be a lot happier if the default was 0.

Posted : 22/03/2021 11:19 pm
fuchsr
(@fuchsr)
Prominent Member

Okay. Not sure what power outages have to do with elephant foot but in any case there’s nothing to agree or disagree with as all I did was present an observation that in my case the defaults seem to work well. I wasn’t arguing that this should be true for everyone, and I certainly wouldn’t have any issues if the devs decided to decouple EF compensation and brim for those who might benefit from it. 

Re resetting it every time? Why not create a custom profile(s) that sets it to 0? Wouldn’t that work for you? 

Posted : 22/03/2021 11:28 pm
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