Jump to content
Ultimaker Community of 3D Printing Experts

Walls vs top and bottom layers

Recommended Posts

When rotating a design for printing,  does it change what Cura considers the outer walls and top/bottom layers?  For example, if I take a box and rotate it on its side for printing, will the side of the box that now sits on the build plate, be considered the bottom layers by Cura?

Share this post

Link to post
Share on other sites
4 hours ago, Rvalecruz said:

will the side of the box that now sits on the build plate, be considered the bottom layers by Cura?



Cura does multiple steps.  One of the early steps is to "slice" which means cura takes each of the layers and represents a plane and intersects that plane with all the triangles in the STL file (an STL file is an unordered collection of triangles - there is no information in there that says which triangle goes with which).  This is done *after* the rotation that you specified so the triangles are already rotated into their new postitions.


At this point (for each slice) cura has a huge list of straight lines in 2 dimensional space (because we intersected with a plane.  Those randomly ordered lines are then linked up into loops.  The edges of those loops are considered the WALLS even if they are "holes" inside the part.  At the same time cura tries to figure out which side of these loops are inside versus outside.


The TOP/BOTTOM areas are figured out differently - obviously everything printed in the very first slice is "bottom" but there can be "bottom" portions half way up the print as well.  TOP/BOTTOM is figured out in 3 dimensions.  Walls are figured out in a single 2 dimensional slice.

Share this post

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

    • Introducing Ultimaker Cura 3.6 | Beta
      Ultimaker Cura 3.6 | Beta is available. It comes with new features, bug fixes, and UX improvements. We would really like to have your feedback on it to make our stable release as good as it can be. As always, you can download the beta for free from our website, for Windows, MacOS, and Linux.
        • Like
      • 83 replies
    • Print Core CC | Red for Ruby
      Q: For some users, abrasive materials may be a new subject matter. Can you explain what it is that makes a material abrasive when you are not sure which print core to use?
      A: Materials which are hard in a solid piece (like metals, ceramics and carbon fibers) will generally also wear down the nozzle. In general one should assume...
        • Like
      • 30 replies
    • "Back To The Future" using Generative Design & Investment Casting
      Designing for light-weight parts is becoming more important, and I’m a firm believer in the need to produce lighter weight, less over-engineered parts for the future. This is for sustainability reasons because we need to be using less raw materials and, in things like transportation, it impacts the energy usage of the product during it’s service life.
        • Like
      • 12 replies

Important Information

Welcome to the Ultimaker Community of 3D printing experts. Visit the following links to read more about our Terms of Use or our Privacy Policy. Thank you!