Empathy List Archives

MH

Mark Harrison

Sun, Jul 22, 2018 6:39 PM

Sometimes I import an external STL file to make some modifications...
resize a hole, etc. To do so, I need to get the dimensions of the
imported object.

Scale markers are useful for this, but usually takes a couple of tries
to get the correct values.

Is there any way in OpenSCAD to retrieve dimensions of objects? Even
dumping out bounding boxes to the console would be great.

Alternatively, any other programs that can print useful information
about an STL file, such as bounding boxes? I realize that STL files
don't have dimension information; just the values are fine.

Sometimes I import an external STL file to make some modifications... resize a hole, etc. To do so, I need to get the dimensions of the imported object. Scale markers are useful for this, but usually takes a couple of tries to get the correct values. Is there any way in OpenSCAD to retrieve dimensions of objects? Even dumping out bounding boxes to the console would be great. Alternatively, any other programs that can print useful information about an STL file, such as bounding boxes? I realize that STL files don't have dimension information; just the values are fine.

JB

Jordan Brown

Sun, Jul 22, 2018 6:55 PM

On 7/22/2018 11:39 AM, Mark Harrison wrote:

Alternatively, any other programs that can print useful information
about an STL file, such as bounding boxes? I realize that STL files
don't have dimension information; just the values are fine.

Text STL files are in a pretty simple format and can be relatively
easily examined in any language.

Here's an awk program that dumps the bounding box for a text STL file:

BEGIN {
    m = 1000000; // Make larger if your model is really large
    maxx = -m;
    minx = m;
    maxy = -m;
    miny = m;
    maxz = -m;
    minz = m;
}

$1 == "vertex" {
    maxx = ($2>maxx ? $2 : maxx);
    minx = ($2<minx ? $2 : minx);
    maxy = ($3>maxy ? $3 : maxy);
    miny = ($3<miny ? $3 : miny);
    maxz = ($4>maxz ? $4 : maxz);
    minz = ($4<minz ? $4 : minz);
}

END {
print minx,miny,minz;
print maxx,maxy,maxz;
}

If what you have is a binary STL file then it's a little harder. How
hard depends on your computer; if you're on a little-endian system (like
Intel-derived systems) then it's not bad, probably a couple of dozen
lines of C.

There's a simple description of the file format at
https://en.wikipedia.org/wiki/STL_(file_format)#Binary_STL

On 7/22/2018 11:39 AM, Mark Harrison wrote: > Alternatively, any other programs that can print useful information > about an STL file, such as bounding boxes? I realize that STL files > don't have dimension information; just the values are fine. Text STL files are in a pretty simple format and can be relatively easily examined in any language. Here's an awk program that dumps the bounding box for a text STL file: BEGIN { m = 1000000; // Make larger if your model is really large maxx = -m; minx = m; maxy = -m; miny = m; maxz = -m; minz = m; } $1 == "vertex" { maxx = ($2>maxx ? $2 : maxx); minx = ($2<minx ? $2 : minx); maxy = ($3>maxy ? $3 : maxy); miny = ($3<miny ? $3 : miny); maxz = ($4>maxz ? $4 : maxz); minz = ($4<minz ? $4 : minz); } END { print minx,miny,minz; print maxx,maxy,maxz; } If what you have is a binary STL file then it's a little harder. How hard depends on your computer; if you're on a little-endian system (like Intel-derived systems) then it's not bad, probably a couple of dozen lines of C. There's a simple description of the file format at https://en.wikipedia.org/wiki/STL_(file_format)#Binary_STL

F

fred_dot_u

Sun, Jul 22, 2018 6:58 PM

I've found it useful to use Meshmixer, a free program, to import STL files.
The Analysis feature has a dimension option which will display a bounding
box for the entire model based on the current orientation. If a model is
irregular, you can use Edit/Transform to rotate it and check the bounding
box again.

Also useful is the Edit/Plane Cut, which allows you to slice the model in
any location, multiple times, to get a different set of bounding boxes,
enabling you to measure accurately, say, a cylinder in the center of the
model, or to better determine a specific dimension.

Obviously, one would not save the sliced model as it would overwrite your
original.

Another great feature is Undo (Control-Z) which lets you perform and measure
a slice, then return to the original model (Control-Z multiple times) and
make other actions.

--
Sent from: http://forum.openscad.org/

I've found it useful to use Meshmixer, a free program, to import STL files. The Analysis feature has a dimension option which will display a bounding box for the entire model based on the current orientation. If a model is irregular, you can use Edit/Transform to rotate it and check the bounding box again. Also useful is the Edit/Plane Cut, which allows you to slice the model in any location, multiple times, to get a different set of bounding boxes, enabling you to measure accurately, say, a cylinder in the center of the model, or to better determine a specific dimension. Obviously, one would not save the sliced model as it would overwrite your original. Another great feature is Undo (Control-Z) which lets you perform and measure a slice, then return to the original model (Control-Z multiple times) and make other actions. -- Sent from: http://forum.openscad.org/

AB

Antonio Bueno

Sun, Jul 22, 2018 9:06 PM

Hi.

Alternatively, any other programs that can print useful information
about an STL file, such as bounding boxes? I realize that STL files
don't have dimension information; just the values are fine.

There is a really old (‘96!) command line tool that you may find useful:
https://github.com/admesh/admesh

Regards,
Antonio B.

Hi. > Alternatively, any other programs that can print useful information > about an STL file, such as bounding boxes? I realize that STL files > don't have dimension information; just the values are fine. There is a really old (‘96!) command line tool that you may find useful: https://github.com/admesh/admesh Regards, Antonio B.

JB

Jamie Bainbridge

Sun, Jul 22, 2018 10:42 PM

On 23 July 2018 at 04:39, Mark Harrison marhar@gmail.com wrote:

Alternatively, any other programs that can print useful information
about an STL file, such as bounding boxes? I realize that STL files
don't have dimension information; just the values are fine.

I wrote a Python script which can do this:
https://www.reddit.com/r/3Dprinting/comments/7ehlfc/python_script_to_find_stl_dimensions/

Jamie

On 23 July 2018 at 04:39, Mark Harrison <marhar@gmail.com> wrote: > Alternatively, any other programs that can print useful information > about an STL file, such as bounding boxes? I realize that STL files > don't have dimension information; just the values are fine. I wrote a Python script which can do this: https://www.reddit.com/r/3Dprinting/comments/7ehlfc/python_script_to_find_stl_dimensions/ Jamie

CG

Clint Goss

Mon, Jul 23, 2018 8:16 AM

… external STL file …
… get the dimensions of the imported object.

I use 3D-Tool. They provide a free STL viewer that is very handy for
measuring between points, vertices, lines, planes, etc.

https://www.3d-tool.com/

-- Clint Goss

Goss.com http://www.goss.com/ ... index of all our web sites

> … external STL file … > … get the dimensions of the imported object. I use 3D-Tool. They provide a free STL viewer that is very handy for measuring between points, vertices, lines, planes, etc. https://www.3d-tool.com/ -- Clint Goss Goss.com <http://www.goss.com/> ... index of all our web sites

AP

Alexander Pruss

Mon, Jul 23, 2018 4:20 PM

Rather than using OpenSCAD's import function, I convert stl files directly to
OpenSCAD polyhedra using my stl2scad.py script:
https://github.com/arpruss/miscellaneous-scad/tree/master/scripts

The latest version of the script puts all the points in an stlObject1_points
list, so you can calculate bounding boxes yourself with:
minima = [for(i=[0:2]) min([for(p=stlObject1_points) p[i]])];
maxima = [for(i=[0:2]) max([for(p=stlObject1_points) p[i]])];

If you just want to see the bounds without converting to a polyhedron, the
bounds.py script will do that.

--
Sent from: http://forum.openscad.org/

Rather than using OpenSCAD's import function, I convert stl files directly to OpenSCAD polyhedra using my stl2scad.py script: https://github.com/arpruss/miscellaneous-scad/tree/master/scripts The latest version of the script puts all the points in an stlObject1_points list, so you can calculate bounding boxes yourself with: minima = [for(i=[0:2]) min([for(p=stlObject1_points) p[i]])]; maxima = [for(i=[0:2]) max([for(p=stlObject1_points) p[i]])]; If you just want to see the bounds without converting to a polyhedron, the bounds.py script will do that. -- Sent from: http://forum.openscad.org/

L

lar3ry

Fri, Jun 7, 2019 5:48 AM

I know this is an old thread, but this may help someone.
I grabbed your excellent python script, stldim.py, and added a little bit at
the end to make it more useful to OpenSCAD users. It's fairly simple, and
solves a problem that I have had trouble with many times; moving an imported
STL file to the origin.

Here is the output for a test.stl, a simple cube not near the origin in any
axis.

L:\3D\Test>stldim.py test.stl
File: test.stl
X size: 30.0
Y size: 20.0
Z size: 13.0
X position: -60.0
Y position: 43.0
Z position: -16.0
-16.0 -3.0
Quadrant: translate([ 60.0 , -43.0 , 16.0 ])
Center: translate([ 45.0 , -53.0 , 9.5 ])

After running this, you simply copy one of the two translate statements and
paste it in front of the imported stl.

"xx Quadrant:" puts the object in the xx quadrant (NE, NW, SW, SE)
"Center:" centres the object in all three dimensions.

stldim.py http://forum.openscad.org/file/t2121/stldim.py

--
Sent from: http://forum.openscad.org/

I know this is an old thread, but this may help someone. I grabbed your excellent python script, stldim.py, and added a little bit at the end to make it more useful to OpenSCAD users. It's fairly simple, and solves a problem that I have had trouble with many times; moving an imported STL file to the origin. Here is the output for a test.stl, a simple cube not near the origin in any axis. L:\3D\Test>stldim.py test.stl File: test.stl X size: 30.0 Y size: 20.0 Z size: 13.0 X position: -60.0 Y position: 43.0 Z position: -16.0 -16.0 -3.0 Quadrant: translate([ 60.0 , -43.0 , 16.0 ]) Center: translate([ 45.0 , -53.0 , 9.5 ]) After running this, you simply copy one of the two translate statements and paste it in front of the imported stl. "xx Quadrant:" puts the object in the xx quadrant (NE, NW, SW, SE) "Center:" centres the object in all three dimensions. stldim.py <http://forum.openscad.org/file/t2121/stldim.py> -- Sent from: http://forum.openscad.org/

L

lar3ry

Tue, Jun 11, 2019 4:45 AM

I have done some more work with Jamie Bainbridge's stldim.py script, and
have come up with an easier way to get the translate() info into OpenSCAD,
in order to move an STL file to be adjacent to or centered on the X,Y,Z
origin.

Running the script in a directory containing an STL file will generate an
OpenSCAD file that may be used as a library that you can include to move the
STL file.

I put it on gihub (I think I got it right), and would appreciate comments or
suggestion.

https://github.com/lar3ry/OpenSCAD---Move-STL-to-origin

--
Sent from: http://forum.openscad.org/

I have done some more work with Jamie Bainbridge's *stldim.py* script, and have come up with an easier way to get the translate() info into OpenSCAD, in order to move an STL file to be adjacent to or centered on the X,Y,Z origin. Running the script in a directory containing an STL file will generate an OpenSCAD file that may be used as a library that you can include to move the STL file. I put it on gihub (I think I got it right), and would appreciate comments or suggestion. https://github.com/lar3ry/OpenSCAD---Move-STL-to-origin -- Sent from: http://forum.openscad.org/

A

arnholm@arnholm.org

Tue, Jun 11, 2019 11:21 AM

On 2019-06-11 06:45, lar3ry wrote:

I have done some more work with Jamie Bainbridge's stldim.py script,
and
have come up with an easier way to get the translate() info into
OpenSCAD,
in order to move an STL file to be adjacent to or centered on the X,Y,Z
origin.

Running the script in a directory containing an STL file will generate
an
OpenSCAD file that may be used as a library that you can include to
move the
STL file.

I put it on gihub (I think I got it right), and would appreciate
comments or
suggestion.

https://github.com/lar3ry/OpenSCAD---Move-STL-to-origin

I tried your python script, but got an error:

ModuleNotFoundError: No module named 'stl'

Then I tried: 'pip3 install stl' which seemed to work. However, when I
ran the script again, I got

python stldim.py
Traceback (most recent call last):
File "stldim.py", line 3, in <module>
from stl import mesh
ImportError: cannot import name 'mesh' from 'stl'
(C:\Python\Python37\lib\site-packages\stl_init_.py)

So apparently there are some dependencies that need clarification.

Here is an alternative approach to the same problem (based on your STL)
using bounding boxes in AngelCAD
https://gist.github.com/arnholm/c06966e575173f9eaaafbac1d30e0c76

Carsten Arnholm

On 2019-06-11 06:45, lar3ry wrote: > I have done some more work with Jamie Bainbridge's *stldim.py* script, > and > have come up with an easier way to get the translate() info into > OpenSCAD, > in order to move an STL file to be adjacent to or centered on the X,Y,Z > origin. > > Running the script in a directory containing an STL file will generate > an > OpenSCAD file that may be used as a library that you can include to > move the > STL file. > > I put it on gihub (I think I got it right), and would appreciate > comments or > suggestion. > > https://github.com/lar3ry/OpenSCAD---Move-STL-to-origin I tried your python script, but got an error: ModuleNotFoundError: No module named 'stl' Then I tried: 'pip3 install stl' which seemed to work. However, when I ran the script again, I got python stldim.py Traceback (most recent call last): File "stldim.py", line 3, in <module> from stl import mesh ImportError: cannot import name 'mesh' from 'stl' (C:\Python\Python37\lib\site-packages\stl\__init__.py) So apparently there are some dependencies that need clarification. Here is an alternative approach to the same problem (based on your STL) using bounding boxes in AngelCAD https://gist.github.com/arnholm/c06966e575173f9eaaafbac1d30e0c76 Carsten Arnholm

discuss@lists.openscad.org

Getting dimensions of imported shape?