Jump to content
Ultimaker Community of 3D Printing Experts

Cura Brim Bug?

Recommended Posts



I've noticed a bug of sorts with the Build Plate Adhesion Type "Brim". It appears the "Brim Only on Outside" of the model doesn't work 100%.


Cura seems to place brim material around internal "islands" of the model so anything that loops around leaving material in the middle. To explain what I mean I've added screenshots of what happens when printing a model with text on the base such as the Benchy or the Banzai Bill model. There is brim material within the letters which "caps" them off.


Is there a fix for this? Can we have a feature where we can remove certain paths by clicking on them to delete?






Edited by cdrose

Share this post

Link to post
Share on other sites

Indeed Cura makes the brim "outside" but it didn't recognice correctly what is "inside".

There are quasi "insides inside insides", tried to visualize this here:untitled-2.jpg.d8c6d31d22633e8b68c641077702d7e1.jpg.63519fce2f74e99af7dd74c10b8fbe60.jpg


If you set the brimline-count to 1 or 2 it becomes better visible how cura thinks, for example the "O"



Because there is part 1 inside part 2 there "must" be A the outline for part 2

and B the outline for part 1

Edited by berndjm

Share this post

Link to post
Share on other sites

It should run a script to detect the next closest edge, if it finds one then don't place brim in there. We should be able to adjust this detection. Therefore when it traced outside the model it would reach the edge of the build plate and know that part was the outside of the model.

Share this post

Link to post
Share on other sites

I am not sure that would be wise to try to implement. Right now, it seems to be following the same rules as programs such as Illustrator use to determine inside and outside.


Rather, I think it would behoove the use to use the settings in Cura to use a secondary object to modify settings of the first object by eliminating the brim. I will see if I can set a thing up to demonstrate what I mean. And, see if theory and reality meet square on.

Share this post

Link to post
Share on other sites

Therefore when it traced outside the model it would reach the edge of the build plate and know that part was the outside of the model


I think it's not so easy to detect the "real outside" and at the same time handle cases where the currently behavior makes sense.

See this simplified use-case:


Here it could be helpful to have the brim also inside the object.


I think to have a adjustable threshold (is this the right word?) for the outside detection would be nice ... but how to handle than the two parts close together like in your 2nd screenshot?

Share this post

Link to post
Share on other sites

I tried to do what I thought would be possible. Again, reality and theory did not mate up nicely. Here was my train of thought:


This is a selection that would be a problem with brims. This would not be fun to trim out as it is a thin object and tiny in detail.



So I was thinking that instead of trying to make the software do something that would be really a pain to operate precisely based on the idea that @berndjm showed in the post above; When is it good/not good to have software decide what is inside or outside? My theory was to use the new feature that allows one model to modify settings of another model. This is in the 'per model settings' dialogue. I have found this to be really most useful in a variety of ways. It has easily become my favorite feature and I use it in almost everything right now.



But, as reality will often do, it will not work because it turns out that brim is not a per model setting. This may be easier to implement though than try to set some sort of other option.

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
      • 92 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!