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Wrong slice in cylinder

Posted: Wed Oct 19, 2016 7:53 am
by Anthony-MCTM
Hello S3D's community,

I'm not English, I hope you will easily understand me.

I have a problem when I slice a cylindrical part.

Although my STL file is in a very high definition, when simplify 3D slices my part it "braids" / "plaits" the cylinder. Look at the photo
2016-10-18 10_14_33-Cortana.png
P1020145.JPG
If someone knows how to fix that problem, I am all ears !

Thanks for your help ;)

Anthony

Re: Wrong slice in cylinder

Posted: Wed Oct 19, 2016 9:28 am
by CompoundCarl
The only time I've seen that happen is when the STL file actually has those same ridges and lines. So check to make sure it isn't a problem with your STL export or tolerance

Re: Wrong slice in cylinder

Posted: Wed Oct 19, 2016 11:44 am
by emkay
I've seen similar results before and it's usually due to the model and not the slicer. Sometimes the way faces are created on curvatures upon export creates some interesting geometry that the slicer then follows.

Re: Wrong slice in cylinder

Posted: Wed Oct 19, 2016 12:40 pm
by Anthony-MCTM
Ok, thanks guys.

The model was export with the best definition of my 3Dsoftware (spaceclaim).

The STL file weighs 200Mo.

How can i have an highter résolution ?

Re: Wrong slice in cylinder

Posted: Wed Oct 19, 2016 5:15 pm
by greybeard
I suggest you reduce the options for exporting the .stl file: high tessellation results in a huge file (as you noted) but, more importantly:
Fine tessellation produces too many triangles/edges/lines that can kill the conversion, while adding nothing to improving part quality.

If your 3D machine's finest print resolution is 0.1mm for layers, you'll never see any 'finer' results on a print no matter how fine your stl tessellation is. On any given layer or between two positons, your stepper motors can't go from A to B in the smallest resolutions that stl files can output so, no point. Compare the gcodes...

Do a test: Export a simple part with different stl output resolutions and print them.

Summary: it's the difference between going from point A to point B with either lot's of incremental steps or fewer larger steps.

Re: Wrong slice in cylinder

Posted: Wed Oct 19, 2016 7:27 pm
by arhi
Anthony-MCTM wrote: How can i have an highter résolution ?
you don't need higher resolution, you need lower resolution. your output resolution can match (be slightly over) your printer resolution. the "best resolution" your software can output is probably around 0.01mm what's the point of that if you are printing with 0.5mm line?

Re: Wrong slice in cylinder

Posted: Thu Oct 20, 2016 6:18 am
by Anthony-MCTM
OK, thanks guys, it was a too hight resolution it cause this issue ! :D

Re: Wrong slice in cylinder

Posted: Thu Oct 20, 2016 7:00 am
by wirlybird
If I am using Fusion 360 to design parts how would I set or know the resolution I am exporting at and set it to best advantage for the print? Never really thought about it until now.

Re: Wrong slice in cylinder

Posted: Thu Oct 20, 2016 9:53 am
by arhi
wirlybird wrote:If I am using Fusion 360 to design parts how would I set or know the resolution I am exporting at and set it to best advantage for the print? Never really thought about it until now.
think about what you are printing with and use common sense .. if your min extruded line is 0.4mm for e.g. you can go and use 0.1mm precision in your export, or even go crazy with 0.05mm but you certainly ain't doing 0.00x :) ...

now every slicer is bit different, number of them don't care much about precision and optimize it themselves, you only waste time with them .. on the other hand some (like s3d) do not (till latest version at all, and with latest version only partially) do that optimisation .. also the way optimization is done you can get weird results ... so Imo the best way to go about it
- select slicer you want to use
- select export tool you are using
- make a 3-5mm thick cylindrical wall so a cylinder with for e.g. 6mm inner dia and 10mm outter dia 10-15mm height .. and export it using different settings and try it out... then do same with elipse 5mm one radius 25mm other radius 3mm wall and then do a 5mm pitch 20tooth pulley ...

dunno about fusion, sw ask about max angle (I never go below 10 degrees) and deviation (I change this from 0.5 to 0.1mm depending on the slicer and what I'm printing) .. so vary them a bit and print few tests :D ... you can, on some slicers, even get some artifacts you want, for e.g. pushing it to 0.05mm I get "smaller holes with more plastic in them - good for heat embedding inserts in" with s3d 3.0 .. does not work any more with 3.1 ..

Re: Wrong slice in cylinder

Posted: Thu Oct 20, 2016 10:10 am
by wirlybird
Thanks for the info. I go from Fusion directly to STL and then to S3D. I usually set Fusion to "high" for output and have not really explored any of the advanced options.
So far items seem to slice ok and quickly but my builds are not that complicated.