Layers/chunks missing in support, and noisy supports

[lukehutch]

Application version 4.7.1

Platform Linux Fedora 32

Printer AnyCubic i3 Mega

Reproduction steps Download files from here: https://www.thingiverse.com/thing:196038

Try slicing file "20150903 WingedVictory Full Scale Decimated to 1MTris.stl"

Use fine settings (0.1mm), and I think everything else on default triggers the problem

Screenshot(s)

Actual results Note the gaps in the support column at the top right, and the weird noise sticking out the side of the model on the bottom left of the screenshot

Expected results Support should not look like this

Project file Linked above

Log file Only the following lines appear in the log when slicing:

2020-10-18 23:14:44,066 - DEBUG - [MainThread] CuraEngineBackend.CuraEngineBackend._onSlicingFinishedMessage [710]: Slicing took 21.17879819869995 seconds 2020-10-18 23:14:44,066 - DEBUG - [MainThread] CuraEngineBackend.CuraEngineBackend._onSlicingFinishedMessage [711]: Number of models per buildplate: {0: 1} 2020-10-18 23:14:44,067 - DEBUG - [MainThread] CuraEngineBackend.CuraEngineBackend._onSlicingFinishedMessage [725]: See if there is more to slice...

[lukehutch]

There's a similar problem with tree supports -- it creates some supports that just appear randomly in the middle of a space. The four layer "blob" in the middle of the following screenshot is several millimeters away from any other material around or below it. (This is a tree support for the same model, with default settings, shown sliced at layer 801, with 0.1mm z-resolution.)

[konskarm]

Hi @lukehutch. I tried reproducing the original issue with the High 0.1 quality profile on an AnyCubic i3 and I do not observe it. Support seems to generate fine and it doesn't have any gaps.

I would like to ask you for the following:

• Please provide a project file (File -> Save Project or Ctrl+S) that clearly displays the problem. This will make sure that it includes all the settings that you change, as well as your printer configuration
• When posting a picture of the Preview Mode, make sure to select Color Scheme -> Line Type, as it makes things clearer
• Your last comment that is related to a Tree Support should end up in a separate ticket, so that there is a different discussion for that (since it is probably a different bug). In this case, since there is already a ticket for tree supports in mid-air (#8570), please post your comment there to keep the discussions in the related issues

[konskarm]

I stand corrected, I can see the problem on the front side of the model. I will put it up for discussion with the team.

[lukehutch]

Thanks for reproducing.

I'll assume that the problem with floating tree supports in my first comment is better covered by bug #8570.

Just updated the original issue text -- I mentioned the second issue was showing at the bottom right of the first screenshot, I meant the bottom left.

Here is a closeup of that part of the model (at waist, back right on the model), with the line type coloring. You can see some useless noisy support material being added.

I suspect this is related to the other problem with breaks in support columns: one is positive noise, one is negative noise.

Here's my saved project, in case you want to exactly reproduce this other problem (since your support rendering looks a bit different from mine).

https://gofile.io/d/0Un22a

[Ghostkeeper]

Looks like a duplicate of https://github.com/Ultimaker/Cura/issues/7191 to me. The Support X/Y distance is removing parts of support up until the point that it disappears. The support should actually be resting on the model, but having too high of a X/Y/Z distance setting makes the gap too big.