basic questions $fn
hi,
i am new into 3d and want to use this tool to make some 3d prints.
first modelling in openscad and then slicing and printing on prusa i3
mk3.
my question about modelling, i havt this simple code:
$fn = 10;
difference() {
cube (size = [40,30,4]);
# translate ([20,10,0]) {
cylinder(d = 7, h = 4);
}
}
now when i render the model the hole does not look round. wehn i alter
the parameter $fn to 100 it looks round. is this parameter $fn just a
visual thing or does my 3d print (after slicing) come out as it looks on
the screen with edges?
and next question: i want to have this plate with a hole. translate
starts from 0 and the hole/cylinder is exact 4 high, as the plate. is
that ok? or do i have to set translet -1 and cylinder high 6, as shown
on the manual and sample?
thank you, claudio
Yes the STL file will be same as shown on the screen. It only contains
triangles so you can't have a round circle.
For 3D FFF printing I use $fa = 6 and $fs = half my filament width to get
good curves without ridiculously small segments.
You should avoid coincident surfaces by subtracting a longer cylinder when
drilling holes. To avoid the extra translate I often use a cylinder twice
as long plus 1 and center = true when drilling.
On 12 October 2017 at 15:38, web@minutella.ch wrote:
hi,
i am new into 3d and want to use this tool to make some 3d prints.
first modelling in openscad and then slicing and printing on prusa i3 mk3.
my question about modelling, i havt this simple code:
$fn = 10;
difference() {
cube (size = [40,30,4]);
# translate ([20,10,0]) {
cylinder(d = 7, h = 4);
}
}
now when i render the model the hole does not look round. wehn i alter the
parameter $fn to 100 it looks round. is this parameter $fn just a visual
thing or does my 3d print (after slicing) come out as it looks on the
screen with edges?
and next question: i want to have this plate with a hole. translate starts
from 0 and the hole/cylinder is exact 4 high, as the plate. is that ok? or
do i have to set translet -1 and cylinder high 6, as shown on the manual
and sample?
thank you, claudio
OpenSCAD mailing list
Discuss@lists.openscad.org
http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
Hello, Claudio.
You will see much more detail in your screen than in your print. For 3D
printing you don't need $fn values as high as the ones needed to show a
smooth curve surface in your monitor. I usually prefer to indicate the
minimum size of a face ($fs) than the number of faces ($fn). See here:
https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/Other_Language_Features#.24fa.2C_.24fs_and_.24fn
If I understand your second question, yes, you have to add a bit of extra
height to the cylinder that does the hole. I personally like adding tiny
extras so I know any .00x-ended value is avoiding coincident faces. An
example of both things:
$fs=0.4;
difference() {
cube([20, 20, 4], true);
translate(-0.001) cylinder(r=4, h=4.002, center=true);
}
2017-10-12 16:38 GMT+02:00 web@minutella.ch:
hi,
i am new into 3d and want to use this tool to make some 3d prints.
first modelling in openscad and then slicing and printing on prusa i3 mk3.
my question about modelling, i havt this simple code:
$fn = 10;
difference() {
cube (size = [40,30,4]);
# translate ([20,10,0]) {
cylinder(d = 7, h = 4);
}
}
now when i render the model the hole does not look round. wehn i alter the
parameter $fn to 100 it looks round. is this parameter $fn just a visual
thing or does my 3d print (after slicing) come out as it looks on the
screen with edges?
and next question: i want to have this plate with a hole. translate starts
from 0 and the hole/cylinder is exact 4 high, as the plate. is that ok? or
do i have to set translet -1 and cylinder high 6, as shown on the manual
and sample?
thank you, claudio
OpenSCAD mailing list
Discuss@lists.openscad.org
http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
--
Regards from Spain,
Antonio
thank you for the first answer.....
i just dont understand exactely your second idea below...
mybe with a small sample script?
You should avoid coincident surfaces by subtracting a longer cylinder
when drilling holes. To avoid the extra translate I often use a
cylinder twice as long plus 1 and center = true when drilling.
my sample:
$fn = 10;
difference() {
cube (size = [40,30,4]);
translate ([20,10,0]) {
cylinder(d = 7, h = 4);
This is what I do:
$fn = 10;
height = 4;
difference() {
cube (size = [40,30,height]);
#translate ([20,10,0])
cylinder(d = 7, h = 2 * height + 1, center = true);
}
Or if I am lazy I just use h = 100;
On 12 October 2017 at 16:02, web@minutella.ch wrote:
thank you for the first answer.....
i just dont understand exactely your second idea below...
mybe with a small sample script?
You should avoid coincident surfaces by subtracting a longer cylinder
when drilling holes. To avoid the extra translate I often use a
cylinder twice as long plus 1 and center = true when drilling.
my sample:
$fn = 10;
difference() {
cube (size = [40,30,4]);
translate ([20,10,0]) {
cylinder(d = 7, h = 4);
hi all....
thank you all for your answers... i think i got that :)
now i am playing and modifying my code....
next question will come ;-)
take care, claudio
--
Sent from: http://forum.openscad.org/