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Ultimaker / Cura

3D printer / slicing GUI built on top of the Uranium framework
GNU Lesser General Public License v3.0
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brim doesn't add to second item if any part is rotated #9420

Open jxer opened 3 years ago

jxer commented 3 years ago

Application Version

4.8

Platform

windows 10

Printer

ender v2

Reproduction steps

added a nut and a screw, when spinning either piece the screw will not add any form of support, remove the nut object and brim comes back

Actual results

only 1 item receives a brim

Expected results

both should receive brim

screw.zip

attached

fvrmr commented 3 years ago

Hi @jxer thank you for your bug report. Could you add a project file (file - save project) instead of stl files. Because when I import these two models both do have a brim, but that is with my settings. A project file contains your settings and printer. So it would be easier to reproduce your issue. Screenshot (119) Thank you in advance.

jxer commented 3 years ago

spin the screw 180 degree's please so the head is resting at the bottom

fvrmr commented 3 years ago

Ah thanks, but get still a brim. Screenshot (125)

If you want me to look at it again a project file is very helpful.

jxer commented 3 years ago

CE3PRO_nut.zip Cura_DrEWFa5gpF

not doing anything special, rotate both items and boom i can't get the screw to take a brim, nor does it print one either.

fvrmr commented 3 years ago

Thank you! The reason why there is no brim created is because the screw does not touch the build plate.

See here at layer 1: Screenshot (127)

By dragging in to the build plate 0.09 mm the screw touches the build plate and the brim is created. Screenshot (128)

But it is weird that I get a brim without dragging the screw into the build plate, switching to different profiles it seems like that's the issue. Could you check if this is also the case for you?

jxer commented 3 years ago

do you mean quality profile? shouldn't it be snapping to the build plate? it does when its a single piece. definitely seems like a bug

Asterchades commented 3 years ago

Check the Mesh Fixes section, making sure that Remove Empty First Layers is checked. That's the only profile-level setting I can think of which might allow that to occur.

GregValiant commented 3 years ago

The screw is touching the build plate with the Z = 0. Because it's an oval head phillips screw the points of the screwdriver cross that are touching the build plate are so miniscule (borderline "infinitely small") that the contact patch is effectively zero so Cura is ignoring them either because they can't be printed, or their size falls below how ever many decimal places Cura works to. I think that's why there isn't any brim since for that part in that Z location there is no first layer. I was able to generate a brim with the Z at -0.01 but there is still no part. AT Z = -0.02 the part starts to print on layer #1. Unfortunately, because it is an oval head the rest of the head doesn't touch the build plate and would require support. Changing the part to a conventional flat head screw makes printing much easier with the head down and I'm sure it would look better. It should be possible to print the oval head with the head "up".

jxer commented 3 years ago

this issue only occurs if there are 2 pieces. I don't have to play around with z axis, if the screw is by itself, only when the nut is added.

GregValiant commented 3 years ago

If I move the nut off the build surface then yes, the screw has a brim at .12 Initial Layer Height so something is going on there between the parts. Grouping them together had no effect. With the Initial Layer Height at .16 and both parts on the surface they both have a brim. I'm not giving up on my "Infinitesimal Points" theory just yet. I'm pinning my hopes on the fact that a taller 1st layer height fixes the problem.

fvrmr commented 3 years ago

do you mean quality profile? shouldn't it be snapping to the build plate? it does when its a single piece. definitely seems like a bug

Yes with super quality 0.12 mm the brim is gone and changing it to dynamic quality 0.16mm the brim is added.

I'm pinning my hopes on the fact that a taller 1st layer height fixes the problem.

Yes changing the initial layer height to 0.16mm is a workaround.

jxer commented 3 years ago

is this going to be listed as a bug and resolved?

fvrmr commented 3 years ago

I will discuss it with the team. Keep you posted!

fvrmr commented 3 years ago

Hi @jxer I have discussed it with the team. But we don't see this as a bug, so we won't fix this. The reason why we don't see this as a bug has to do with the models. Because the nut is flat and the screw head not, the initial layer of the screw is less than 0,12 mm so there is no layer. That explains why it is visible with another profile. Hope this makes sense to you. Please reach out if you have more questions.

Ghostkeeper commented 3 years ago

this issue only occurs if there are 2 pieces. I don't have to play around with z axis, if the screw is by itself, only when the nut is added.

This is because of the Remove Empty First Layers setting. If the screw is the only item on the build plate, the first layer is empty and it then gets removed, effectively moving down the screw by 1 layer. However if you also have a bolt on the build plate, the first layer is no longer empty. Cura assumes that the screw is supposed to be in that position relative to the bolt, and so it won't automatically move the print down any more.