Why do these gaps appear in this sliced model?

Hi all,

I sliced the attached model with the PLA 0.2 profile with Skeinforge and was wondering why the gaps (marked in the pictures) appear in the sliced model? Can I do something with the settings to get rid of them? They don't show up when the model is sliced with the PLA 0.3 profile.

Much thanks in advance,

Niels

Hi Niels,

Are you sure it is not just a RepetierHost rendering artifact? You could try viewing your G-Code online here and see how it compares.

Regards,
Neil Darlow

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I try to write with consideration for all nationalities. Please let me know if something is unclear.
Printing with Mendel90 from fedora 25 using Cura, FreeCAD, MeshLab, OpenSCAD, Skeinforge and Slic3r tools.

Remember that sketchup isn't a proper 'solid' modeller too and it's circles are rather 'hacky'.

Try modelling the same problem area with more sections in your tube....

Thanks guys,

The gaps do show up in the print so it isn't just an artefact. The strange thing is that when I slice only one segment or block of the "dodecagonal" model the gaps don't turn up in the block (photo attached). As soon as I add another segment the problem shows. I guess maybe it has something to do with the orientation (different angle ) of the blocks which causes problems for Skeinforge? A remarkable thing is that the gaps don't show up if I slice the model with PLA 0.3 instead of 0.2. I've also attached two stl files and gcode files in case anyone wants to take a closer look.

Regards,

Niels
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Edit: I'm pretty sure the model is manifold in Sketchup by the way. I use several pluggins to verify the object is solid.

Edited 1 time(s). Last edit at 12/17/2013 10:03AM by Nilez.

Your STL files are non manifold, so will give odd effects when you slice them.

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[www.hydraraptor.blogspot.com]

Hi Chris,

So they're not solid . Scratching my head now about what to do about it since inside Sketchup the model proves solid. Can it get non-manifold in the process of converting it to STL? I'm sorry if I'm asking these things in the wrong place. Just wondering if someone maybe recognizes this problem. But thank you very much for checking my stl's, because I know where the problem lies!

Meanwhile I've hit google to search for a method for repairing stl's and have used "netfabb cloud service" to repair my stl's. I've attached the fixed file by Netfabb, but the gaps still show up after slicing .

Edited 1 time(s). Last edit at 12/17/2013 02:57PM by Nilez.

The fixed versions seems to slice correctly for me.

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[www.hydraraptor.blogspot.com]

So you don't get the gaps displayed in the pictures of the first post Chris? Then it must be something with Skeinforge on my system.

Edited 1 time(s). Last edit at 12/17/2013 05:57PM by Nilez.

Actually I do with the 0.2mm PLA profile. I tested with a 0.2mm ABS profile I use with a 0.45mm nozzle and it worked.

Also the 0.3mm PLA profile works, so it must be depend on line width and layer height, which determines exactly where it samples the STL. I can't see anything wrong with the STL but I never get errors like that with SF myself.

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[www.hydraraptor.blogspot.com]

Ok so bit of a weird thing going on here then. I'll see if slightly changing the dimensions of my model will eliminate the problem. Thanks again for testing Chris!!

Have you thought of trying openscad? It would seem better suited to that sort of print.

Hi Ralph,

I use sketchup because I've learned to work with it before I got into 3d printing, and now I simply don't have time to learn another programme. But with having to redraw a part when a dimension is off I wish I had learned to work with a parametric cad programme . Maybe when I have the time again, I'll have a go at it. I'm also very visually oriented so I'm a bit scared of Openscad

Edited 1 time(s). Last edit at 12/27/2013 10:59AM by Nilez.

Openscad is very easy to learn and you can render very quickly to see what your code does. It took me about 2 hours to learn the basics of it which are sufficient for all my needs so far.
Most of the tutorials and manuals are heavy reading. This is a well written (imo) beginner's tutorial :
[www.makerbot.com]
I haven't opened sketchup since I looked at it.

Edited 1 time(s). Last edit at 12/28/2013 04:39PM by Ralph.Hilton.

Ok you've made me curious. hopefully I'll have the same experience once I have the time to give it a whirl! Thanks for the link!

Edited 1 time(s). Last edit at 01/02/2014 05:18PM by Nilez.

Hi Guys,

Just wanted to let you know that if you first export your sketchup file to .dae and then convert it to stl with another programme (I used Meshlab), the model is sliced correctly with Skeinforge (no more gaps in this case). So a little work-around if the normal stl-export of Sketchup gives you problems during the slicing process.

Regards,

Nilez