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Missing part of layer for certain layer height

Posted: Sat Mar 12, 2016 5:02 am
by Luke321
When trying to print this fish: http://www.thingiverse.com/thing:1276095

Using a layerheight of 0.2 and 100% height of first layer (also 0.2) I get this weird error where part of a layer in the middle is completely missing.

Image

When using 0.21 layerheight the part comes out fine.

Any ideas or is this a bug?

Re: Missing part of layer for certain layer height

Posted: Sat Mar 12, 2016 8:22 am
by dkightley
This may be an error in the mesh. Push the .stl file through the online repair service and see if it cures the issue.
https://netfabb.azurewebsites.net/

Re: Missing part of layer for certain layer height

Posted: Sun Mar 13, 2016 1:55 am
by Luke321
Forgot to mention that I already did that, tried meshmixer repair and netfabb online repair, both say no errors. Problem remains.

Re: Missing part of layer for certain layer height

Posted: Sun Mar 13, 2016 1:36 pm
by danlad1631
I've just posted with the same issue here viewtopic.php?f=8&t=4800

Any thoughts on how to solve this?

Re: Missing part of layer for certain layer height

Posted: Mon Mar 14, 2016 3:54 am
by Luke321
Changing the layerheight resolved the problem, but now I have to check all models before printing...

Re: Missing part of layer for certain layer height

Posted: Mon Mar 14, 2016 4:03 am
by danlad1631
What did you change the height to? I was printing at 2.5.

Re: Missing part of layer for certain layer height

Posted: Mon Mar 14, 2016 9:03 am
by kutterkoeter
I also frequently see issues when using 0.2 resolution (usually parts of the top layers missing / messed up), changing the layer height slightly (e.g. 0.199) fixes this.

I suspect there is something going on with floating point truncating or roundoff errors, multiples of 0.1 are famously hard to represent in floating point precision.

Re: Missing part of layer for certain layer height

Posted: Tue Mar 15, 2016 3:37 pm
by p1um1oco
I am also having a missing layer, but the open part of that missing layer is filled in. There is an internal open void to weight the piece with pennies.

This is an OpenScad model of a Chess pawn that i created. this missing layer only happens when using the 0.2 layer height. If i change it to 0.1999 or 0.2001 then there is no issue, but at 0.2 there is a bug that causes a layer to go missing. mine seems to be about the same height at what looks in the above photo. My issue happens at layer 23. And it is only for this piece.

Image

Re: Missing part of layer for certain layer height

Posted: Wed Mar 16, 2016 5:24 am
by CompoundCarl
p1um1oco wrote:I am also having a missing layer, but the open part of that missing layer is filled in.
I would suggest making a different thread for your issue and attaching your factory file. That's the best way to get help, since that way others can test your settings and make recommendations.

Re: Missing part of layer for certain layer height

Posted: Thu Mar 17, 2016 1:07 pm
by danlad1631
I changed the layer height as suggested and it's fine.