Hi, I am trying to manipulate an STL file and I started by using the difference command. At the moment, I am using a cube to 'take away' material from the STL file. The cube is of a temporary size and position. Here is the code ( from https://drive.google.com/file/d/1qkBsjmyGhAaEsH8V1E1WoS5jOCYzfPzB/view?usp=sharing ): difference(){ import("Squirrel_Picnic_Table_-_topbracket a.stl"); cube([10,10,10]); } What happens is there are all sorts of 'ghosting' with gaps/holes in the model, an image that shows this is https://drive.google.com/file/d/1Wh_Uh-ojot5LHmzwKCcwSS9K6OASkzCH/view?usp=sharing If I take the cube away, it looks fine https://drive.google.com/file/d/1Tvj065N9BHBMK4lgl6VBnUS-7ROQqTTH/view?usp=sharing The STL file I am importing is https://drive.google.com/file/d/1lvmfqu2qTnOG4KcGboypfI8srrJFfGuu/view?usp=sharing Does anyone know why this happens and how I can resolve this ghosting effect please? Thanks, Richard.

You need to set the convexity parameter in the import statement, ss https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/STL_Import_and_Export#import On Sat, 22 Jan 2022 at 09:32, Richard Thomas <richdthomas@gmail.com> wrote: > Hi, > > I am trying to manipulate an STL file and I started by using the > difference command. > > At the moment, I am using a cube to 'take away' material from the STL file. > > The cube is of a temporary size and position. > > Here is the code ( from > https://drive.google.com/file/d/1qkBsjmyGhAaEsH8V1E1WoS5jOCYzfPzB/view?usp=sharing > ): > > difference(){ > import("Squirrel_Picnic_Table_-_topbracket a.stl"); > cube([10,10,10]); > } > > > What happens is there are all sorts of 'ghosting' with gaps/holes in the > model, an image that shows this is > https://drive.google.com/file/d/1Wh_Uh-ojot5LHmzwKCcwSS9K6OASkzCH/view?usp=sharing > > If I take the cube away, it looks fine > https://drive.google.com/file/d/1Tvj065N9BHBMK4lgl6VBnUS-7ROQqTTH/view?usp=sharing > > The STL file I am importing is > https://drive.google.com/file/d/1lvmfqu2qTnOG4KcGboypfI8srrJFfGuu/view?usp=sharing > > > Does anyone know why this happens and how I can resolve this ghosting > effect please? > > Thanks, > > Richard. > _______________________________________________ > OpenSCAD mailing list > To unsubscribe send an email to discuss-leave@lists.openscad.org >

 Hi,

 I am trying to manipulate an STL file and I started by using the
 difference command.

As was said very recently, we need to increase the default values of the convexity parameters.  This is wasting everyone's time, and has for years. Jon On 1/22/2022 4:43 AM, nop head wrote: > You need to set the convexity parameter in the import statement, ss > https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/STL_Import_and_Export#import > > On Sat, 22 Jan 2022 at 09:32, Richard Thomas <richdthomas@gmail.com> > wrote: > > Hi, > > I am trying to manipulate an STL file and I started by using the > difference command. > >

Hi, Thanks for that, I read up about convexity and set it to 10, as I found this "Setting it to 10 should work fine for most cases.". That did the trick. I also vote that the default value gets increased :) Thanks for your help. Richard. On Sat, 22 Jan 2022 at 12:52, jon <jon@jonbondy.com> wrote: > As was said very recently, we need to increase the default values of the > convexity parameters. This is wasting everyone's time, and has for years. > > Jon > On 1/22/2022 4:43 AM, nop head wrote: > > You need to set the convexity parameter in the import statement, ss > https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/STL_Import_and_Export#import > > On Sat, 22 Jan 2022 at 09:32, Richard Thomas <richdthomas@gmail.com> > wrote: > >> Hi, >> >> I am trying to manipulate an STL file and I started by using the >> difference command. >> >> >> _______________________________________________ > OpenSCAD mailing list > To unsubscribe send an email to discuss-leave@lists.openscad.org >