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Slicing error - missing layers

Posted: Sat Nov 22, 2014 2:22 pm
by dsegel
See the attached files. When I slice the stl with S3D there's a section missing from the rocket's exhaust inner piece from about layers 23-59. When I slice it with Slic3r it's there. I've attached a screenshot of the problem area and the gcode file from Slic3r as well as Factory File.

I'd like to know if this is a problem with the model, a bug in S3D, or an error in my process.

Re: Slicing error - missing layers

Posted: Sat Nov 22, 2014 6:14 pm
by BaudR8
dsegel wrote:See the attached files. When I slice the stl with S3D there's a section missing from the rocket's exhaust inner piece from about layers 23-59. When I slice it with Slic3r it's there. I've attached a screenshot of the problem area and the gcode file from Slic3r as well as Factory File.

I'd like to know if this is a problem with the model, a bug in S3D, or an error in my process.
It appears that the unwanted slicing behavior is due to the model itself (as is with most cases, if not all, that I've seen). If you do a cross-section view (I find this very useful when finding errors in a model) it looks like there's a whole band missing from the exhaust.
errorInModel.png
Using your stock slicing settings, I also saw the slicing behavior you're talking about:
Normal.png
I went into Advanced and checked the merge all outlines option and it seems to fix the error and get a better slicing, however, it will fill in the exhaust completely.
Merge.png

Re: Slicing error - missing layers

Posted: Sat Nov 22, 2014 6:20 pm
by dsegel
Awesome, thank you. I'll see if there's some way to fix it externally without filling it all in.

Re: Slicing error - missing layers

Posted: Sat Nov 22, 2014 6:27 pm
by jimc
the problem is how it modeled. i took the model in s3d and used the cross section view. i attached a pic. you can see the bottom section is a separate piece from the upper with a gap in the middle. im not sure what this piece is or if that gap is supposed to be there. it may be just a modeled support structure that gets removed after the print. in any case you can see its made in a "V" and the walls get thinner and thinner as it goes up. what is going on is eventually the wall gets so thin that your printer cant print it. to get it to print i needed to reduce the extrusion width to .25mm. if that "V" was a solid piece you would have no issue. currently when s3d figures perimeters it wont do a single extrusion. there always has to be an inner and outer perimeter so the wall cant really be less than double your extrusion width. there is a bit of fudge factor there because s3d will overlap lines a bit but not that much. if im not mistaken and what i am told is there is now a setting in slic3r that will tell it to do thin walls as a single extrusion. hopefully that made sense.
Screen Shot 2014-11-22 at 6.04.56 PM.png

Re: Slicing error - missing layers

Posted: Sat Nov 22, 2014 6:29 pm
by jimc
haha oh well baudr8 beat me to it lol

Re: Slicing error - missing layers

Posted: Sat Nov 22, 2014 7:14 pm
by BaudR8
jimc wrote:haha oh well baudr8 beat me to it lol
i was grabbing screencaps as quick as I could to beat you, I had a feeling you would be posting in a model error thread ; )