Nikolay_Po

It is Debian 10 Linux, 4.19.0-18-amd64. I used "Ultimaker_Cura-4.13.1.AppImage" file to run Cura slicer. Yes, I saw exactly this behavior on the printer.

Of course. If I'll find something interesting again, I'll show you, for sure.

@GregValiant, I found G-code file with this problem. It was generated such way, with a bug, twice. Once I noticed the problem and second, after I saved the project with "Cube100_bug_possible" name I re-sliced the cube again and stored it with this new name. And the problem is clearly visible in secondary sliced G-code too. Look an attachment. Now I started the same Cura 4.13.1 on the same PC. Have tried to slice cube again but can't get the problem, can't repeat this bad result. Cube100_bug_possible_Gcode.zip

Hello, Greg. Indeed, I have tried to open mine project on different PC (the same Debian Linux, the same Cura 4.13.1). None problem seen. I will try to find G-code file with a problem later. Mention should be noted that originally I choose Concentric Top/Bottom pattern with "Connect Top/Bottom Polygon" option checked. Then I switched to ZigZag pattern. And my first impression when I saw the printing process, was: Is it filling ZigZag with interleaving, like it did with Concentric pattern? Nevertheless I was unable to recreate the problem with my own project file on different computer. I'll come back if will find a file with the problem.

Hi! There is a bug in Monotonic Top/Bottom function. It is visible in Preview mode while simulating print head move. If I'm printing a cube, the diagonal filling of bottom layers is doubling at one half of bottom layer. You can try slice and run preview of project attached. When Cura fills the bottom by zig-zag moves. It fills a half by 45 degrees moves, a triangle between three corners of bottom square. Instead of continue to fill second half toward last corner, it returns and become fill already printed bottom again. Then, after doubling bottom layer at a half of cube projection, it continues to fill the rest of layer normally, without overprinting. A huge overextrusion is observed on a half of volume. Excessive material is spreading by next layer moves and the result is terrible. To return correct behaivour it is enough to uncheck the "Monotonic Top/Bottom" function. Cube100_bug_possible.3mf