Why is this so heavy to OpenScad?
Hello,
I'm trying to build a cage that will be later subtracted from a rounded box,
but the cage is so heavy to OpenScad (version 2019/05) that I'm not being
able to do anything further.
Is this a bug? Any other way of building the cage to be lighter?
Marcos
use <./MCAD/boxes.scad>;
$fa=1;
$fs=1;
//----------------------
cage();
//----------------------
cubW = 100;
cubL = 100;
cubH = 80;
wall = 2.5;
//--------------------------------------------------------------------------
module cage()
{
difference() {
curv = 26;
difference() {
roundedBox( [cubH, cubL, cubW], curv, true );
roundedBox( [cubH-2.0*wall,cubL-2.0*wall, cubW-2.0*wall], curv-2, true);
}
dl = -1.0;
dx = cubW/3+2;
dy = cubL/3+2;
dz = cubH/3+2;
for ( sdx = [ -1, 0, +1 ] ) {
for ( sdy = [ -1, 0, +1] ) {
for ( sdz = [ -1, 0, +1] ) {
translate([sdx*dx, sdy*dy, sdz*dz])
roundedBox([cubW/3-dl,cubL/3-dl,cubH/3-dl],3, false);
}
}
}
}
}
//--------------------------------------------------------------------------
//--------------------------------------------------------------------------
--
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I'd guess it's because you've set $fa to be 1.
On Sun, Nov 10, 2019, 1:07 PM MVAckel via Discuss <
discuss@lists.openscad.org> wrote:
Hello,
I'm trying to build a cage that will be later subtracted from a rounded
box,
but the cage is so heavy to OpenScad (version 2019/05) that I'm not being
able to do anything further.
Is this a bug? Any other way of building the cage to be lighter?
Marcos
use <./MCAD/boxes.scad>;
$fa=1;
$fs=1;
//----------------------
cage();
//----------------------
cubW = 100;
cubL = 100;
cubH = 80;
wall = 2.5;
//--------------------------------------------------------------------------
module cage()
{
difference() {
curv = 26;
difference() {
roundedBox( [cubH, cubL, cubW], curv, true );
roundedBox( [cubH-2.0*wall,cubL-2.0*wall,
cubW-2.0*wall], curv-2, true);
}
dl = -1.0;
dx = cubW/3+2;
dy = cubL/3+2;
dz = cubH/3+2;
for ( sdx = [ -1, 0, +1 ] ) {
for ( sdy = [ -1, 0, +1] ) {
for ( sdz = [ -1, 0, +1] ) {
translate([sdx*dx, sdy*dy, sdz*dz])
roundedBox([cubW/3-dl,cubL/3-dl,cubH/3-dl],3, false);
}
}
}
}
}
//--------------------------------------------------------------------------
//--------------------------------------------------------------------------
--
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You can try using a higher value of $fa or using different values in
different calls to roundedBox so you only use the high precision where you
need it most.
Your use case may vary.
On Sun, Nov 10, 2019, 1:43 PM Max Bond max.o.bond@gmail.com wrote:
I'd guess it's because you've set $fa to be 1.
On Sun, Nov 10, 2019, 1:07 PM MVAckel via Discuss <
discuss@lists.openscad.org> wrote:
Hello,
I'm trying to build a cage that will be later subtracted from a rounded
box,
but the cage is so heavy to OpenScad (version 2019/05) that I'm not being
able to do anything further.
Is this a bug? Any other way of building the cage to be lighter?
Marcos
use <./MCAD/boxes.scad>;
$fa=1;
$fs=1;
//----------------------
cage();
//----------------------
cubW = 100;
cubL = 100;
cubH = 80;
wall = 2.5;
//--------------------------------------------------------------------------
module cage()
{
difference() {
curv = 26;
difference() {
roundedBox( [cubH, cubL, cubW], curv, true );
roundedBox( [cubH-2.0*wall,cubL-2.0*wall,
cubW-2.0*wall], curv-2, true);
}
dl = -1.0;
dx = cubW/3+2;
dy = cubL/3+2;
dz = cubH/3+2;
for ( sdx = [ -1, 0, +1 ] ) {
for ( sdy = [ -1, 0, +1] ) {
for ( sdz = [ -1, 0, +1] ) {
translate([sdx*dx, sdy*dy,
sdz*dz])
roundedBox([cubW/3-dl,cubL/3-dl,cubH/3-dl],3, false);
}
}
}
}
}
//--------------------------------------------------------------------------
//--------------------------------------------------------------------------
--
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MCAD's roundedBox is not particularly efficient.
Try this version (copied from example006.scad)
module rounded_cube(size,r,center=false)
{
s = is_list(size) ? size : [size,size,size];
translate(center ? -s/2 : [0,0,0])
hull() {
translate([ r, r, r]) sphere(r=r);
translate([ r, r,s.z-r]) sphere(r=r);
translate([ r,s.y-r, r]) sphere(r=r);
translate([ r,s.y-r,s.z-r]) sphere(r=r);
translate([s.x-r, r, r]) sphere(r=r);
translate([s.x-r, r,s.z-r]) sphere(r=r);
translate([s.x-r,s.y-r, r]) sphere(r=r);
translate([s.x-r,s.y-r,s.z-r]) sphere(r=r);
}
}
It doesn't have "sides only" version, but it should be easier to
compute, just replace the main loop body with your cage holes to call
that instead:
//roundedBox([cubW/3-dl,cubL/3-dl,cubH/3-dl],3, false);
rounded_cube([cubW/3-dl,cubL/3-dl,cubH/3-dl],3, true);
Also you can save a bit more computation if you ignore the center
column of "holes" like this:
if (!(sdx == 0 && sdy == 0)) translate([sdxdx, sdydy, sdz*dz])
Hans
On Sun, Nov 10, 2019 at 2:45 PM Max Bond max.o.bond@gmail.com wrote:
You can try using a higher value of $fa or using different values in different calls to roundedBox so you only use the high precision where you need it most.
Your use case may vary.
On Sun, Nov 10, 2019, 1:43 PM Max Bond max.o.bond@gmail.com wrote:
I'd guess it's because you've set $fa to be 1.
On Sun, Nov 10, 2019, 1:07 PM MVAckel via Discuss discuss@lists.openscad.org wrote:
Hello,
I'm trying to build a cage that will be later subtracted from a rounded box,
but the cage is so heavy to OpenScad (version 2019/05) that I'm not being
able to do anything further.
Is this a bug? Any other way of building the cage to be lighter?
Marcos
use <./MCAD/boxes.scad>;
$fa=1;
$fs=1;
//----------------------
cage();
//----------------------
cubW = 100;
cubL = 100;
cubH = 80;
wall = 2.5;
//--------------------------------------------------------------------------
module cage()
{
difference() {
curv = 26;
difference() {
roundedBox( [cubH, cubL, cubW], curv, true );
roundedBox( [cubH-2.0*wall,cubL-2.0*wall, cubW-2.0*wall], curv-2, true);
}
dl = -1.0;
dx = cubW/3+2;
dy = cubL/3+2;
dz = cubH/3+2;
for ( sdx = [ -1, 0, +1 ] ) {
for ( sdy = [ -1, 0, +1] ) {
for ( sdz = [ -1, 0, +1] ) {
translate([sdx*dx, sdy*dy, sdz*dz])
roundedBox([cubW/3-dl,cubL/3-dl,cubH/3-dl],3, false);
}
}
}
}
}
//--------------------------------------------------------------------------
//--------------------------------------------------------------------------
--
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I played around a bit with this and I have to say, the output from MCAD's
roundedBox is horrible. People have complained when I criticize MCAD, but
I'm sorry, this is just ridiculous:
http://forum.openscad.org/file/t2477/mcad_box.png
This "rounded" box has a bunch of extra polygons because of whatever
craziness is going on with the "rounding". A new user should not encounter
a result like this in the "standard" library. If you want to make it work
anyway then you can do it by putting "render()" in front of your difference
command. But if you use the rounded box posted above it runs in 4s on my
machine, without any trouble (except that the result is wrong because it
always rounds all the edges). Note also that you don't need two
differences, since the inner one subtracts one thing and then the outer one
just subtracts more.
If you want a library that actually works and is supported, I suggest trying
BOSL or BOSL2.
https://github.com/revarbat/BOSL2/wiki
The following code based on BOSL2 runs in 0s for me and actually produces
the same thing as the original code:
include<BOSL2/std.scad>
$fa=1;
$fs=1;
cage();
cubW = 100;
cubL = 100;
cubH = 80;
wall = 2.5;
module cage()
{
curv = 26;
dl = -1.0;
dx = cubW/3+2;
dy = cubL/3+2;
dz = cubH/3+2;
difference(){
cuboid( [cubH, cubL, cubW], rounding=curv, edges=edges("Z")); // Edges
in the Z direction are rounded
cuboid( [cubH-2.0wall,cubL-2.0wall, cubW-2.0*wall], rounding=curv-2,
edges=edges("Z"));
grid3d(n=[3,3,3],spacing=[dx,dy,dz])
cuboid([cubW/3-dl,cubL/3-dl,cubH/3-dl],rounding=3);
}
}
--
Sent from: http://forum.openscad.org/
On 11/10/2019 2:32 PM, adrianv wrote:
http://forum.openscad.org/file/t2477/mcad_box.png
[ MCAD's ] "rounded" box has a bunch of extra polygons because of whatever
craziness is going on with the "rounding".
That looks really familiar. I have a rounded-end-cylinder polygon
module that I use in a number of places, that I happen to be using
today, and it has some of the same issues. Or did, until I got
obsessive and fixed several of them.
Without looking at the sources, it looks like it isn't so much doing
anything stupid as it is using naïve techniques, building the edges out
of cylinders and the corners out of spheres. Unless you're really
careful, the faces on low-poly corners like that won't line up. It also
looks like it's got the faces of the round things aligning with the
sides of the box, without accounting for the fact that OpenSCAD's
polygon-cylinders have a diameter measured vertex-to-vertex, not
face-to-face. It needs
function adj(d, sides) = d/cos(360/sides/2);
which will give you the diameter (or radius) to use to get a diameter of
"d" measured face-to-face.
To get it simpler just the hull of 8 spheres.
A domingo, 10/11/2019, 22:37, Jordan Brown openscad@jordan.maileater.net
escreveu:
On 11/10/2019 2:32 PM, adrianv wrote:
http://forum.openscad.org/file/t2477/mcad_box.png http://forum.openscad.org/file/t2477/mcad_box.png
[ MCAD's ] "rounded" box has a bunch of extra polygons because of whatever
craziness is going on with the "rounding".
That looks really familiar. I have a rounded-end-cylinder polygon module
that I use in a number of places, that I happen to be using today, and it
has some of the same issues. Or did, until I got obsessive and fixed
several of them.
Without looking at the sources, it looks like it isn't so much doing
anything stupid as it is using naïve techniques, building the edges out of
cylinders and the corners out of spheres. Unless you're really careful,
the faces on low-poly corners like that won't line up. It also looks like
it's got the faces of the round things aligning with the sides of the box,
without accounting for the fact that OpenSCAD's polygon-cylinders have a
diameter measured vertex-to-vertex, not face-to-face. It needs
function adj(d, sides) = d/cos(360/sides/2);
which will give you the diameter (or radius) to use to get a diameter of
"d" measured face-to-face.
OpenSCAD mailing list
Discuss@lists.openscad.org
http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
On 11/10/2019 2:37 PM, Jordan Brown wrote:
function adj(d, sides) = d/cos(360/sides/2);
BTW, trig/computer tidbit of the day: Alexa gets acos( ) and asin( )
completely wrong.
For instance, she says that asin(0.5) is 0.0087, and that acos(0.5) is
1.5621. (Correct are 0.52 and 1.05.) Actually, it appears that all
asin( ) results are about zero, and all acos( ) results are about 1.57.
Also, for sin(x) and cos(x), x is in degrees, but for asin( ) and acos(
) the answer appears to be in radians.
I guess Alexa was distracted during her high school trig class.
I tentatively suspect that they did acos(degrees_to_radians(x)) instead
of radians_to_degrees(acos(x)).
I filed a bug report.
I've submitted a pull request to MCAD (
https://github.com/openscad/MCAD/pull/66 ), to improve roundedBox.
It should work fine as a drop-in replacement for boxes.scad.
Due to potential issues with backwards compatibility, I've left it
open for discussion if the approach I used is the best option.
In order to be more consistent with native OpenSCAD modules, i gave
the new module a slightly different interface, and a different name:
"roundedCube".
Calling "roundedBox" module will still work, and use the new
hull-based implementation, but will echo deprecation warnings.
In the meantime if you don't want to wait for that to be officially
merged, you can directly download the updated file here:
https://raw.githubusercontent.com/openscad/MCAD/e08302349e0e1bf77f6e13a3948386e2ec134def/boxes.scad
Hans
On Sun, Nov 10, 2019 at 4:54 PM Jordan Brown
openscad@jordan.maileater.net wrote:
On 11/10/2019 2:37 PM, Jordan Brown wrote:
function adj(d, sides) = d/cos(360/sides/2);
BTW, trig/computer tidbit of the day: Alexa gets acos( ) and asin( ) completely wrong.
For instance, she says that asin(0.5) is 0.0087, and that acos(0.5) is 1.5621. (Correct are 0.52 and 1.05.) Actually, it appears that all asin( ) results are about zero, and all acos( ) results are about 1.57. Also, for sin(x) and cos(x), x is in degrees, but for asin( ) and acos( ) the answer appears to be in radians.
I guess Alexa was distracted during her high school trig class.
I tentatively suspect that they did acos(degrees_to_radians(x)) instead of radians_to_degrees(acos(x)).
I filed a bug report.
OpenSCAD mailing list
Discuss@lists.openscad.org
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Thank you guys. The new implementation is really lightning fast compared to
the old one. Solved the problem nicely.
--
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