[Solved] Brim - much too much  

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Antoninus
(@antoninus)
Eminent Member

Hi!

How do I get rid of all the not wanted brim? Makes me crazy.
I played around with many settings. then all the brim is gone, or much too much.

I attached pictures with the problem, my settings, how it should be (only skirt, NO brim, support ONLY under object) and  and and how the object looks in bottom view.

Support & brim should be like here:
object only bottom view

Best Answer by Neophyl:

What you are calling a brim is not actually a brim.  In 3d printing a brim connects to the part and helps bed adhesion by making it have a larger surface area in contact with the bed.  From your own settings you havve it set 

What you want to remove is the support first layer, which is the zig zag pattern that it always adds under support on the bed.  The dark green areas you point out are the interface layers.  Here's the bad news, you cant.  Slicer is very aggressive with support outside of the parts.  There are many open issues on github about it, some dating back years.

You could change support to only on bed if you don't want any on your parts but if your design has an overhang located over another part then that will stop the overhang getting any support.

You need to learn the art of using modifiers.  Personally I use support enforcers rather than blockers to control where I want support.  For example if you add a cylinder modifier under that wheel rim you can size it to control where support is placed.  Slice, check, resize, slice, check repeat as needed.  

With modifiers be aware that they aren't area of effect.  They apply where they intersect with the model.  So for example if you add a support enforcer on an overhang and place a support blocker below it in the free space the support WILL go right through the support blocker.  Thats because you have defined something that needs support and as the blocker is NOT intersecting with the part to turn the support off it gets generated.  Basically blockers aren't keep out areas like many assume they are.  Its one reason I use enforcers and then set the support settings to Enforcers only.  You can then get much more targeted supports, with some work.

I've been playing with the pre-alpha 2.3.0 and that allows you to 'paint' areas on the model where you want support which makes things so much easier.  I will be glad when that is released.

If you want save your project as a .3mf, zip it up and attach it here. (needs to be zipped or the forum wont accept it).  I can then add some enforcers for you and re-upload it for you as an example of what you need to do currently.

This topic was modified 4 months ago 2 times by Antoninus
Posted : 07/07/2020 10:41 pm
Antoninus
(@antoninus)
Eminent Member

See the first picture. That's new to me that a slicer puts support -on top- of the object.
How can I stop that?

Thank you very much for help!!

Posted : 07/07/2020 10:49 pm
Antoninus
(@antoninus)
Eminent Member

I must say correctly: the on-op support at the picture, in the middle, happens because the object has little overhang there.
So Prusaslicer puts support there. I could adjust it with the angle setting.
But generrly support is too much.

The problem is that there is always too much support, not only under the object - outside the object and prucaslicer makes a brim additionally to the support.

The unneeded support in the middle of the object in picture is a good example. In this case the surface gets bad in that area, because of this excessive and unneeded support.
And it's a waste of filament and print time.

 

 

 

Posted : 08/07/2020 12:12 am
Neophyl
(@neophyl)
Noble Member

What you are calling a brim is not actually a brim.  In 3d printing a brim connects to the part and helps bed adhesion by making it have a larger surface area in contact with the bed.  From your own settings you havve it set 

What you want to remove is the support first layer, which is the zig zag pattern that it always adds under support on the bed.  The dark green areas you point out are the interface layers.  Here's the bad news, you cant.  Slicer is very aggressive with support outside of the parts.  There are many open issues on github about it, some dating back years.

You could change support to only on bed if you don't want any on your parts but if your design has an overhang located over another part then that will stop the overhang getting any support.

You need to learn the art of using modifiers.  Personally I use support enforcers rather than blockers to control where I want support.  For example if you add a cylinder modifier under that wheel rim you can size it to control where support is placed.  Slice, check, resize, slice, check repeat as needed.  

With modifiers be aware that they aren't area of effect.  They apply where they intersect with the model.  So for example if you add a support enforcer on an overhang and place a support blocker below it in the free space the support WILL go right through the support blocker.  Thats because you have defined something that needs support and as the blocker is NOT intersecting with the part to turn the support off it gets generated.  Basically blockers aren't keep out areas like many assume they are.  Its one reason I use enforcers and then set the support settings to Enforcers only.  You can then get much more targeted supports, with some work.

I've been playing with the pre-alpha 2.3.0 and that allows you to 'paint' areas on the model where you want support which makes things so much easier.  I will be glad when that is released.

If you want save your project as a .3mf, zip it up and attach it here. (needs to be zipped or the forum wont accept it).  I can then add some enforcers for you and re-upload it for you as an example of what you need to do currently.

Posted : 08/07/2020 8:03 am
towlerg
(@towlerg)
Honorable Member

IMHO Brim is great, it costs nothing in terms over overall time to print or material used. Make 'em big. Much better a few minutes added on to total print time and post processing than your creation detaching itself part way thro. I've noticed that for some odd shapes PrusaSlicer generates a skirt that crosses the brim which is pretty pointless, so I lose the skirt.

Posted : 08/07/2020 12:36 pm
Antoninus
(@antoninus)
Eminent Member

Thank you! I understand.
Especially for beginners it is better to have more support and brim than necessary. The support overhang also has advantages, as it is easier to remove. At least in accessible places. But if a part takes over 6h at 0.2 I don't need more to print as needed.
O.K., If that's the way it is I live with it.

I expressed myself somewhat misleadingly because I spoke too much about brim.
But I would call the zig-zag pattern (light green) as a brim as it goes around printing mass -  the support (dark green). A "support brim".

I will play around with Enforcer. If I absolutely cannot manage, I do a zip, thanks!
Every slicer has its advantage. In cura its the support feature. Support only under the object, no extra brim and can be adjusted in % and much more to adjust. Very easy no need to fix by hand.

Posted : 08/07/2020 1:05 pm
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