trying to difference text block from cube
Total nube trying to get started with OpenSCAD...
I have the following code that is partially working the way I'd hoped. If I
run only companyName(), I get what I want (an indented area with raised
letters).
When I try to difference it from a cube, it becomes letters etched into a
two dimensional rectangle positioned away from the cube.
My goal is to be able to create a reusable text block that I can imprint on
my parts. I want this to be raised text in a recessed rectangle.
Any help would be most appreciated!
use <fontmetrics.scad>;module companyName(x, y, z,height) {
textDepth=1; border=1; textSpacing=.5;
usableHeight=height-2border-3textSpacing; topTextHeight=usableHeight/2;
bottomTextHeight=usableHeight/3; font = "Arial"; topText = "Top Text";
bottomText = "Bottom Text"; topTextLength = measureText(topText,
font=font, size=topTextHeight); bottomTextLength =
measureText(bottomText, font=font, size=bottomTextHeight);
echo("topTextLength", topTextLength); echo("bottomTextLength",
bottomTextLength); translate([x-2textDepth,y,z]) {
difference() { if (topTextLength > bottomTextLength) {
cube([2textDepth, topTextLength+2border+3textSpacing, height]);
} else { echo("here"); cube([2textDepth,
bottomTextLength+2border+3textSpacing, height]); }
translate([textDepth,border, border]) { if (topTextLength >
bottomTextLength) { cube([2textDepth,
topTextLength+border+textSpacing, height-2border]); } else {
cube([2textDepth, bottomTextLength+border+textSpacing, height-2*border]);
} } } translate([textDepth, border+textSpacing,
height-border-topTextHeight-textSpacing]) { rotate([90,0,90]) {
linear_extrude(textDepth)
drawWrappedText(topText,font=font,size=topTextHeight,halign="justify");
//text(text, size=topTextHeight); } }
translate([textDepth, border+textSpacing, border+textSpacing]) {
rotate([90,0,90]) { linear_extrude(textDepth)
text(bottomText, size=bottomTextHeight); } } }}module
notWorking() { difference() { cube([4, 50, 50]);
companyName(4, 0, 0, height=10); }}module working() { companyName(4,
0, 0, height=10);}
--
Sent from: http://forum.openscad.org/
On 7/6/2020 1:34 AM, jordanthompson wrote:
Total nube trying to get started with OpenSCAD...
I have the following code that is partially working the way I'd hoped.
If I run only companyName(), I get what I want (an indented area with
raised letters).
When I try to difference it from a cube, it becomes letters etched
into a two dimensional rectangle positioned away from the cube.
My goal is to be able to create a reusable text block that I can
imprint on my parts. I want this to be raised text in a recessed
rectangle.
Any help would be most appreciated!
You have two things going on.
The first is easy. It's a preview rendering problem called Z-fighting.
When you difference two objects that share a face, the renderer can't
figure out whether the face is there or not. The solution is to ensure
that the thing that you are subtracting, the negative space, extends
past the boundary of the thing you're subtracting from. In this
particular case, the easy thing to do is to offset the companyName() by
just a little, perhaps:
module notWorking() {
difference() {
cube([4, 50, 50]);
translate([0.01,-0.01,-0.01])
companyName(4, 0, 0, height=10);
}
}
Z-fighting most obviously affects F5 previews rather than F6 renders,
because of the algorithms used. However, F6 can be vulnerable to
similar effects when the locations of the surfaces involved are derived
from math that can yield imprecise results.
The second and harder, and what I think you're asking about, is that you
aren't thinking of difference() correctly. Remember what your
companyName() looks like. You are removing that material from the
cube, so the result is the negative of it. It sounds like you're
thinking that in
difference() {
A();
B();
}
that B will somehow replace a part of A. (But how could it? B is an
object and an infinite amount of empty space; how much of that empty
space would replace part of A?)
If you want it to behave the way you're thinking, you have to arrange
that B is the negative of what you want to remain.
That requires a little rearranging.
Simplifying, your current notWorking() is:
difference() {
cube(); // big cube
difference() {
cube(); // A
cube(); // B
}
linear_extrude() text();
}
That is, you are taking a cube A, removing another cube B to form an
inset, and then adding some text, and then subtracting the result from
the big cube.
In arithmetic notation, you've got (bigcube - ((A - B) + text)). You
want ((bigcube - B) + text), that you're going to take your object,
subtract away an inset, and then put some text into that inset. That
expression doesn't work for you, because you want the B and "text" to
come together in one module, so you want to algebraically transform it
to (bigcube - (negative - text)).
It doesn't quite work like arithmetic, but it's close. In arithmetic, a
double negative is a positive. A-(A-B) is equal to B. In OpenSCAD CSG,
a result can never be negative, so A-B can be anything from zero to A
and A-(A-B) can't be more than A. Strictly, it's set differencing
rather than arithmetic differencing.
You need to be subtracting the inset, except the text, like so:
difference() {
cube(); // big cube
difference() {
cube(); // negative
linear_extrude() text();
}
}
Note that your first cube, the one I labelled "positive", is not
required. It's material that you expect to remain from the object being
imprinted; it isn't part of the "negative space".
Here's what you want companyName() to produce:
Note that this scheme is based solely on differencing - you cannot use
it to make text that will extend outside the original "big cube". Doing
that would require removing the inset as one step, and then adding the text.
Here's what you need. All I've done is to remove cube A and move the
text inside the difference() so that it's being subtracted from cube B.
Oh, and I renamed "notWorking" to "nowWorking" :-)
use <fontmetrics.scad>;
module companyName(x, y, z,height) {
textDepth=1;
border=1;
textSpacing=.5;
usableHeight=height-2*border-3*textSpacing;
topTextHeight=usableHeight/2;
bottomTextHeight=usableHeight/3;
font = "Arial";
topText = "Top Text";
bottomText = "Bottom Text";
topTextLength = measureText(topText, font=font, size=topTextHeight);
bottomTextLength = measureText(bottomText, font=font, size=bottomTextHeight);
echo("topTextLength", topTextLength);
echo("bottomTextLength", bottomTextLength);
translate([x-2*textDepth,y,z]) {
difference() {
translate([textDepth,border, border]) {
if (topTextLength > bottomTextLength) {
cube([2*textDepth, topTextLength+border+textSpacing, height-2*border]);
} else {
cube([2*textDepth, bottomTextLength+border+textSpacing, height-2*border]);
}
}
translate([textDepth, border+textSpacing, height-border-topTextHeight-textSpacing]) {
rotate([90,0,90]) {
linear_extrude(textDepth)
drawWrappedText(topText,font=font,size=topTextHeight,halign="justify");
//text(text, size=topTextHeight);
}
}
translate([textDepth, border+textSpacing, border+textSpacing]) {
rotate([90,0,90]) {
linear_extrude(textDepth)
text(bottomText, size=bottomTextHeight);
}
}
}
}
}
module nowWorking() {
difference() {
cube([4, 50, 50]);
translate([0.01,-0.01,-0.01]) companyName(4, 0, 0, height=10);
}
}
module working() {
companyName(4, 0, 0, height=10);
}
nowWorking();
Like so:
On 7/6/2020 8:49 AM, Jordan Brown wrote:
On 7/6/2020 1:34 AM, jordanthompson wrote:
Total nube trying to get started with OpenSCAD...
I have the following code that is partially working the way I'd
hoped. If I run only companyName(), I get what I want (an indented
area with raised letters).
When I try to difference it from a cube, it becomes letters etched
into a two dimensional rectangle positioned away from the cube.
My goal is to be able to create a reusable text block that I can
imprint on my parts. I want this to be raised text in a recessed
rectangle.
Any help would be most appreciated!
You have two things going on.
The first is easy. It's a preview rendering problem called
Z-fighting. When you difference two objects that share a face, the
renderer can't figure out whether the face is there or not. The
solution is to ensure that the thing that you are subtracting, the
negative space, extends past the boundary of the thing you're
subtracting from. In this particular case, the easy thing to do is to
offset the companyName() by just a little, perhaps:
module notWorking() {
difference() {
cube([4, 50, 50]);
translate([0.01,-0.01,-0.01])
companyName(4, 0, 0, height=10);
}
}
Z-fighting most obviously affects F5 previews rather than F6 renders,
because of the algorithms used. However, F6 can be vulnerable to
similar effects when the locations of the surfaces involved are
derived from math that can yield imprecise results.
The second and harder, and what I think you're asking about, is that
you aren't thinking of difference() correctly. Remember what your
companyName() looks like. You are removing that material from the
cube, so the result is the negative of it. It sounds like you're
thinking that in
difference() {
A();
B();
}
that B will somehow replace a part of A. (But how could it? B is an
object and an infinite amount of empty space; how much of that empty
space would replace part of A?)
If you want it to behave the way you're thinking, you have to arrange
that B is the negative of what you want to remain.
That requires a little rearranging.
Simplifying, your current notWorking() is:
difference() {
cube(); // big cube
difference() {
cube(); // A
cube(); // B
}
linear_extrude() text();
}
That is, you are taking a cube A, removing another cube B to form an
inset, and then adding some text, and then subtracting the result from
the big cube.
In arithmetic notation, you've got (bigcube - ((A - B) + text)). You
want ((bigcube - B) + text), that you're going to take your object,
subtract away an inset, and then put some text into that inset. That
expression doesn't work for you, because you want the B and "text" to
come together in one module, so you want to algebraically transform it
to (bigcube - (negative - text)).
It doesn't quite work like arithmetic, but it's close. In arithmetic,
a double negative is a positive. A-(A-B) is equal to B. In OpenSCAD
CSG, a result can never be negative, so A-B can be anything from zero
to A and A-(A-B) can't be more than A. Strictly, it's set
differencing rather than arithmetic differencing.
You need to be subtracting the inset, except the text, like so:
difference() {
cube(); // big cube
difference() {
cube(); // negative
linear_extrude() text();
}
}
Note that your first cube, the one I labelled "positive", is not
required. It's material that you expect to remain from the object
being imprinted; it isn't part of the "negative space".
Sigh. I changed the labels as I wrote the message, and missed one.
Should be "Note that your first cube, the one I labelled A, is not
required".
Here's what you want companyName() to produce:
Note that this scheme is based solely on differencing - you cannot use
it to make text that will extend outside the original "big cube".
Doing that would require removing the inset as one step, and then
adding the text.
Here's what you need. All I've done is to remove cube A and move the
text inside the difference() so that it's being subtracted from cube
B. Oh, and I renamed "notWorking" to "nowWorking" :-)
use <fontmetrics.scad>;
module companyName(x, y, z,height) {
textDepth=1;
border=1;
textSpacing=.5;
usableHeight=height-2*border-3*textSpacing;
topTextHeight=usableHeight/2;
bottomTextHeight=usableHeight/3;
font = "Arial";
topText = "Top Text";
bottomText = "Bottom Text";
topTextLength = measureText(topText, font=font, size=topTextHeight);
bottomTextLength = measureText(bottomText, font=font, size=bottomTextHeight);
echo("topTextLength", topTextLength);
echo("bottomTextLength", bottomTextLength);
translate([x-2*textDepth,y,z]) {
difference() {
translate([textDepth,border, border]) {
if (topTextLength > bottomTextLength) {
cube([2*textDepth, topTextLength+border+textSpacing, height-2*border]);
} else {
cube([2*textDepth, bottomTextLength+border+textSpacing, height-2*border]);
}
}
translate([textDepth, border+textSpacing, height-border-topTextHeight-textSpacing]) {
rotate([90,0,90]) {
linear_extrude(textDepth)
drawWrappedText(topText,font=font,size=topTextHeight,halign="justify");
//text(text, size=topTextHeight);
}
}
translate([textDepth, border+textSpacing, border+textSpacing]) {
rotate([90,0,90]) {
linear_extrude(textDepth)
text(bottomText, size=bottomTextHeight);
}
}
}
}
}
module nowWorking() {
difference() {
cube([4, 50, 50]);
translate([0.01,-0.01,-0.01]) companyName(4, 0, 0, height=10);
}
}
module working() {
companyName(4, 0, 0, height=10);
}
nowWorking();
Like so:
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Discuss@lists.openscad.org
http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
Genius!!! Thanks very much for your help and spoon-feeding (we Jordan's have
to help each other out :-).)
--
Sent from: http://forum.openscad.org/