Jump to content
UltiMaker Community of 3D Printing Experts

Noob - looking for simple explanation - What is skin ?


Recommended Posts

Posted (edited) · Noob - looking for simple explanation - What is skin ?

"Skin" generally refers to the top and bottom layers.  Sometimes the word "mesh" is used (but a Mesh can also refer to a model in Cura).  If you are printing a solid box (no lid or opening on the top) the "brim" or "Skirt" get printed first around the periphery of the model.  Brims help hold models down.  Skirts just get the plastic flowing (and can give you a look at how level the bed is).

Next the walls get printed.  If you have a .4 nozzle and the line width is set to .4 then the wall thickness should be a multiple of the line width.  A wall 1.2 wide will take 3 passes - 2 inner-walls and then 1 outer-wall.  If the setting for "additional wall" is checked then after the outer-wall the print head will go around the inside one more time and add a 3rd inner wall.  The printer will then print the bottom "Skin" by filling in the entire area between the walls.  in the case of the box, it's the bottom layer you will be able to see when the print is done and off the build plate.  It is the base for the whole print and it's critically important that it goes down right and adheres to the build plate.

The printer keeps adding walls around the outside, and skins on the inside until the Bottom Thickness and/or Bottom Layers is reached.  As the print goes up from there, the walls keep going (except for the Additional Wall" which is only for skin) and "Infill" takes the place of "skin".  Once the print gets to the top of the box, skin replaces the infill and you want the last skin to look nice so you might even iron your skin.  That is the S&M part of 3D printing that nobody ever really talks about.

Do you need skin?  No.  If you slice the box with top layers set to "0" it will not have a top skin and the infill will go right to the top of the walls.  If you then set Infill to 0, you will have an empty box with no top.  If you set bottom layers to 0 you will print a rectangular tube - no bottom, no top, no infill.

Time to hit Thingiverse (you can get there from inside Cura) and get a calibration cube to play with.


Always remember that the #1 use of pigskin is not the making of American footballs.  The #1 use of pigskin is to hold pigs together.


Edited by GregValiant
  • Link to post
    Share on other sites

    Posted · Noob - looking for simple explanation - What is skin ?

    Wow @GregValiant THANKS for that thorough explanation.


    You're saying that the layers printed on the bottom and top of the model, excluding the inner and outer walls are the skin (am I correct ?). I'm still confused though, under the shell category there is no way to set number  or thickness of skin (just top surface skin layers), but I can change Top\Bottom thickness. I'm concluding that there are  Top\Bottom layers (adjustable thickness ) and skin layers (non adjustable thickness), my question is what is the difference  or relationship between Top\Bottom and skin ?

  • Link to post
    Share on other sites

    Posted · Noob - looking for simple explanation - What is skin ?

    I guess it's a question of semantics.  The number of "topmost skin layers" can be set.  I would think that is the "show" surface(s).  The layers just below would be, well, layers.  The "Skin Layers" can have a separate speed setting and can be ironed to enhance the finish.  


    The bottom surface picks up the pattern of the top of the build plate and it's facing down so nothing can really be done with it to enhance the finish.  Maybe that's why in Cura it isn't considered a "skin".  Maybe it would be a "sole"?


  • Link to post
    Share on other sites

    Create an account or sign in to comment

    You need to be a member in order to leave a comment

    Create an account

    Sign up for a new account in our community. It's easy!

    Register a new account

    Sign in

    Already have an account? Sign in here.

    Sign In Now
    • Our picks

      • UltiMaker Cura 5.3 stable released
        In this stable release, Cura 5.3 achieves yet another huge leap forward in 3D printing thanks to material interlocking! As well as introducing an expanded recommended print settings menu and lots of print quality improvements. Not to mention, a whole bunch of new printer profiles for non-UltiMaker printers!
          • Thanks
        • 21 replies
      • Here it is. The new UltiMaker S7
        The UltiMaker S7 is built on the success of the UltiMaker S5 and its design decisions were heavily based on feedback from customers.
        So what’s new?
        The obvious change is the S7’s height. It now includes an integrated Air Manager. This filters the exhaust air of every print and also improves build temperature stability. To further enclose the build chamber the S7 only has one magnetically latched door.
        The build stack has also been completely redesigned. A PEI-coated flexible steel build plate makes a big difference to productivity. Not only do you not need tools to pop a printed part off. But we also don’t recommend using or adhesion structures for UltiMaker materials (except PC, because...it’s PC). Along with that, 4 pins and 25 magnets make it easy to replace the flex plate perfectly – even with one hand.
        The re-engineered print head has an inductive sensor which reduces noise when probing the build plate. This effectively makes it much harder to not achieve a perfect first layer, improving overall print success. We also reversed the front fan direction (fewer plastic hairs, less maintenance), made the print core door magnets stronger, and add a sensor that helps avoid flooding.

        The UltiMaker S7 also includes quality of life improvements:
        Reliable bed tilt compensation (no more thumbscrews) 2.4 and 5 GHz Wi-Fi A 1080p camera (mounted higher for a better view) Compatibility with 280+ Marketplace materials Compatibility with S5 project files (no reslicing needed) And a whole lot more  
        Curious to see the S7 in action?
        We’re hosting a free tech demo on February 7.
        It will be live and you can ask any questions to our CTO, Miguel Calvo.
        Register here for the Webinar
          • Like
        • 18 replies
      • UltiMaker Cura Alpha 🎄 Tree Support Spotlight 🎄
        Are you a fan of tree support, but dislike the removal process and the amount of filament it uses? Then we would like to invite you to try this special release of UltiMaker Cura. Brought to you by our special community contributor @thomasrahm
        We generated a special version of Cura 5.2 called 5.3.0 Alpha + Xmas. The only changes we introduced compared to UltiMaker Cura 5.2.1 are those which are needed for the new supports. So keep in mind, this is not a sneak peek for Cura 5.3 (there are some really cool new features coming up) but a spotlight release highlighting this new version of tree supports.  
          • Like
        • 21 replies
    • Create New...