mechamecha

Thank you, nallath. OK, I'll do github in the future.

Sorry about that. I started my own topic about the unrelated issues. But the original issue remains: Cura 4.5 drops nozzle straight down into purged filament, causing it to be dragged into the print. Original poster hasn't specified which printer they're using, but I'm experiencing this with a UM2 (as is geert_2 it seems). Not firmware related, because I can confirm this didn't happen with 4.1; it only started when I switched to 4.5. Also not a "prime blob" issue, because that's never been an option for UM2. If anyone still believes I'm "hijacking" this thread, I'll refrain from posting here and start my own topic concerning this issue...

Just started using Cura 4.5 after sticking with 4.1 for quite a while because of an issue with supports missing on bottom layers. (@burtoogle was kind enough to figure out a workaround in this thread.) However, I've discovered a couple of other strange issues: 1) After slicing, then changing certain settings (e.g. roof support settings), the "preview" and "save to file" options continue to remain visible with no option to reslice. In order to reslice, I have to change an unrelated setting, then reset it back to its original value. 2) When switching between printers (UM3 and UM2 in my case), sometimes settings will mysteriously vanish. To get them to reappear, I'll have to restart Cura. Or I can go into settings and individually deselect, then reselect them. (These aren't printer specific settings that are supposed to disappear; they're settings that should be there, like support settings, for example.) 3) With UM2, start gcode does the expected nozzle purge, but then drops the nozzle straight down into the purged filament before moving over to start printing, causing it to drag the whole mess into the print. I don't think this is a firmware issue with the UM2, because Cura 4.1 didn't cause this to happen.

Sure. Doesn't really look like there's a legit solution for the filament dragging problem, though. I was the first one to reply to your original post after three days, reporting that I was experiencing the same issue.

Another thing I noticed was that when changing certain settings after slicing in Cura 4.5, it doesn't give you any option to reslice like it should. For example, support roof settings. It will continue to just show "preview" and "save to file" options. I have to change another setting, then set it back to its original value to reslice.

Prime blob has never been an option for UM2. Regarding the vanishing settings, I'm not talking about printer-specific settings. Things like support settings are sometimes disappearing. To get them back I need to restart Cura. Or go into settings and deselect, then reselect.

Thanks for the reply. What you say is certainly what I've observed with UM3, with which I have had no problems. For me, that prime blob is simply squished down by the print head and I haven't noticed it dragging at all. The problem is with UM2, and I don't think it's a firmware thing, because this wasn't happening with Cura 4.1. Just started using 4.5, which is when it started being an issue. It does seem to drop the nozzle straight down into the middle of the purged filament. Another problem I've noticed with Cura 4.5 is that settings sometimes mysteriously vanish when I switch from one printer config to another (e.g., UM3 to UM2).

Oh, wow. Sorry about that. When I bought my UM3 last year, I did quite a bit of searching on the internet and could not find any way to do this. Before posting, I did another search on this forum and didn't find anything new about it, so I just figured nothing had changed. Thanks!

I'm having the same issue with my Ultimaker 2. The printer does a nozzle purge first, then it lowers the nozzle straight down into the purged filament and drags the mess into the print. UM2_start_gcode_problem.3mf

Aha! But your solution had me check out other support settings that I had hidden. I set Support Stair Step Maximum Width to 0 which worked!

Hmm. It worked for the UM3, but not for UM2, unfortunately... UM2_support_bug.3mf

Excellent! Thank you so much! I guess I should've posted this problem here a long time ago instead of suffering in silence!

Sure! Thanks. UM3_support_bug.3mf

It would be awfully nice if the Ultimaker 3 would allow printing with only one material loaded. Most of my print jobs are single material, so the second spool often sits on the back of the printer for extended periods of time. I like to keep my filaments bagged with desiccant so they don't absorb moisture and collect dust.

Cura supports haven't worked for me since 4.1. With every new release, I hope that the bug I've experienced has been fixed, but it hasn't. Just tried 4.5, same problem. It's quite frustrating, because I'd like to take advantage of some of Cura's newer features, but I continually have to go back to 4.1 just to get reliable supports. Large areas of supports are just not being generated for the first several layers, so when Cura decides to finally generate them properly at a higher layer, they're not adhering to the bed. I've attached some screenshots below to clearly show this major problem which has persisted through multiple versions. I sure hope Ultimaker can finally fix this nasty bug soon.