OpenSCAD用户手册/FAQ

一般问题

OpenSCAD怎么念?

OpenSCAD的发音为Open - ESS - CAD

显示问题

预览功能似乎完全不起作用

Force Goldfeather

在一些系统中，特别是跑在Intel GPUs上的Windows系统，往往会存在一些老旧或易崩溃的OpenGL驱动。这会影响差集或交集操作的有关预览渲染。

下列步骤常用于改善这种问题：Edit->Preferences->Advanced->Force Goldfeather (参见截图)。

预览版中那些奇怪的闪烁失真是怎么回事？

OpenSCAD中重合面的显示问题

这通常是由于不同对象共用一个或多个面所导致的，例如：

difference() {
  cube(20, center = true);
  cylinder(r = 10, h = 20, center = true);
}

在大多数情况下，最终渲染出的结果是完好的，but it's recommended to make the cuts a little bit larger to prevent this type of issues.

Note that this issue may also occur with faces that are not even visible in the final result, for example because they're removed by a difference() operation. This is an artifact of the library used for drawing the preview. See this discussion for an example and a workaround.

参见：https://en.wikipedia.org/wiki/Z-fighting

为什么模型中的一些部分(如孔洞)无法正确地渲染出来？

OpenSCAD display issue with convexity setting too low

This can happen when using features like linear_extrude() or when importing objects. The convexity of the objects is not known. For more complex objects, the convexity parameter can be used to specify the value. Note that higher values will cause a slowdown in preview.

difference() {
    linear_extrude(height = 15 /* , convexity = 2 */) {
        difference() {
            square([50, 50]);
            translate([10, 10]) circle(5);
        }
    }
    translate([25, 25]) cube([5, 5, 40], center = true);
}

See also https://en.wikipedia.org/wiki/Convexity_%28mathematics%29

为什么用F5可以显示出我的模型而F6却不行？

OpenSCAD polyhedron with flipped face

This can be caused by polyhedrons with flipped faces.

This can be visualized in "Thrown Together" display mode. See misordered faces for details.

points = [[5,5,0],[5,-5,0],[-5,-5,0],[-5,5,0],[0,0,3]];
faces = [[0,1,4],[1,2,4],[2,3,4],[3,4,0],[1,0,3],[2,1,3]];
polyhedron(points, faces);

If the model imports external STL files, see also import related question.

为神马预览速度那么慢？

http://forum.openscad.org/Why-is-for-so-slow-tp11511p11531.html

This is hard to explain, but in essence, having intersections as the negative objects in difference is expensive. The preview rendering algorithm only allows having primitive objects as negatives, and everything else has to be unpacked.

For example (using A+B = union() / A-B = difference() / A*B = intersection()):

A - B*C - D*E

becomes: A-B-D + A-B-E + A-C-D + A-C-E

..and if A is more complex:

A+B - C*D - E*F

becomes: A-C-E + A-C-F + A-D-E + A-D-F + B-C-E + B-C-F + B-D-E + B-D-F

All combinations have to be rendered, which can take some time, especially on older GPUs, and especially on low-end Intel GPUs.

导入数据问题

为什么用F5可以显示我导入的STL文件，而F6却不行？

This is mostly caused by bad STL files, the best bet is to verify the STL file in a tool like Blender, MeshLab or NetFabb and fix the issues. In essence the model needs to be manifold to be processed in OpenSCAD.

The reason for the model still showing up in preview mode is that there is no real geometry calculation going on yet. The preview simply draws the triangles from the STL.

There is one specific issue that causes problems called "Zero faces" (meaning the STL contains triangles with zero area because all 3 points are on one line) which are currently not handled well in OpenSCAD.

Using MeshLab

MeshLab has a filter to remove zero faces by flipping edges of polygons

Filters -> Cleaning and Repairing -> Remove T-Vertices by Edge-Flip.

Set the Ratio to a very high value (e.g. 1000000), otherwise it's possible the model gets distorted.

Using Blender

Blender has a 3D-Printing-Toolbox Plug-in (needs to be enabled in the UserSettings) which can show issues with the STL file. See http://wiki.blender.org/index.php/Extensions:2.6/Py/Scripts/Modeling/PrintToolbox

Using NetFabb/Microsoft cloud service

The Microsoft 3D Model Repair service can help with fixing STL files. Make sure to read the service conditions before posting files. See https://modelrepair.azurewebsites.net/

在导入DXF文件时，我收到了"Unsupported DXF Entity"警告，这是什么意思？

DXF import sometimes produces warning messages like Unsupported DXF Entity 'SPLINE' (1c1) in "file.dxf". This means the DXF file is using features that the OpenSCAD importer does not know how to handle. The importer will simply ignore those unknown entities which could result in an incomplete model.

When using Inkscape, the easiest way to produces DXF files without unsupported entities is to convert all Bezier curves to short line segments using

Extensions -> Modify Path -> Flatten Beziers

The value given in the dialog will determine the length of the line segments. Lower values will produce smoother results, but also much more line segments. As export file format, use "Desktop Cutting Plotter (AutoCAD DXF R14)".

A more detailed tutorial is available at http://repraprip.blogspot.de/2011/05/inkscape-to-openscad-dxf-tutorial.html

导出数据问题

我要怎样做才能从一个脚本中导出多个零件呢？

Answer based on comments in related issue on github https://github.com/openscad/openscad/pull/1534#issuecomment-227024209

There is a way to generate a bunch of geometric primitives and export them as STL files from a single script, without commenting/uncommenting code.

There is a variable, PARTNO, that indicates which part is being exported in the current run. If PARTNO is 'undef', then nothing is exported.

Image exported with PARTNO=0

 PARTNO = undef; // default part number
 
 module tree() {
   color("green") cylinder(r1 = 12, r2 = 1, h = 30);
   // ...
 }
 
 module trunk() {
   color("brown") cylinder(r = 3, h = 10);
   // ...
 }
 
 module base() {
   color("white") translate([-10, -10, 0]) cube([20, 20, 5]);
   // ...
 }
 
 if (PARTNO == 1) tree();
 if (PARTNO == 2) trunk();
 if (PARTNO == 3) base();
 
 // optionally use 0 for whole object
 if (PARTNO == 0) {
   base();
   translate([0, 0, 5]) trunk();
   translate([0, 0, 15]) tree();
 }

When working interactively, the PARTNO variable at the top of the file can be set to the number of the part that will be shown/exported from the GUI.

It's possible to automate the process of exporting all of the parts by writing a shell script on MacOS or Linux, or a batch file on Windows. The shell script would look something like this:

 # export parts as STL
 openscad -DPARTNO=1 -o tree.stl model.scad
 openscad -DPARTNO=2 -o trunk.stl model.scad
 openscad -DPARTNO=3 -o base.stl model.scad
 
 # export image of all the parts combined
 openscad -DPARTNO=0 -o model.png model.scad

Running this script once from the command line will export all of the parts to separate files.

我要怎样做才能导出比当前窗口分辨率更高的截图呢？

Right now that is not possible from the GUI as the images are restricted to the actual display context so using the File->Export->Export As Image menu will always export at viewport resolution.

It is however possible to generate higher resolution images via command line using the --imgsize parameter. This uses a separate drawing context to generate the image which is size limited only by memory and the graphics driver. For example on Linux the Mesa driver for Intel UHD Graphics 620 (Kabylake GT2) seems to max out at an image resolution of about 16000x16000.

 $ openscad --imgsize 16000,16000 -o CSG.png CSG.scad
 ECHO: version = [2019, 1, 0]
 Compiling design (CSG Products normalization)...
 Normalized CSG tree has 6 elements
 $ file CSG.png 
 CSG.png: PNG image data, 16000 x 16000, 8-bit/color RGB, non-interlaced

语言问题

为什么我写下a = a + 1这条语句却会得到一条错误消息?

http://forum.openscad.org/A-A-1-tp11385p11411.html

First of all, the question why we have these "limitations" will become more clear once we start better exploiting the opportunities.

• We need a "reduce" function to help collecting information depending on a list of input. Recursion is fine, but people tend to struggle with it and we could offer some help.
• We should probable disallow any attempt of reassignment, to make it more clear what's going on. The only real reason we partially allow it is to allow cmd-line variable overrides.

To help think about things:

• Imagine every expression in OpenCAD being executed in parallel. Any dependency of existing expressions must be made explicit by hierarchical grouping. This will kill the idea of iterating in order to accumulate information.
• In terms of functions: Imagine a function expression being something you'd type into a spreadsheet cell. Not totally mappable, but it might help framing it.

Now, we could add all kinds of sugar to help people apply their existing programming problem solving skills. Question is more if it really helps us, secondary who will spearhead the design of such language extensions, as we currently don't really have attachment for these ideas on the dev-team.

If you think about the OpenSCAD language as something similar to HTML, but for 3D modeling, you'd still have a need for various programs generating code in this language (similar to the plethora of HTML generators out there). There exist a number of tools for helping with OpenSCAD code generation from existing programming languages (python, ruby, C++, haskell, clojure off the top of my head) and there are tools offering Javascript interfaces for similar purposes (OpenJSCAD, CoffeeSCAD). Until we have a really good reason to do so in OpenSCAD proper, and a really good candidate for which language to support, I think it's better to keep these things separate.

see also for help: List Comprehension, Tips & Tricks, Recursive Functions

用户界面问题

OpenSCAD并不适于我的GTK桌面主题

You may need to install package "qt5-style-plugins" on debian based systems, then set environment variable when calling openscad QT_QPA_PLATFORMTHEME=gtk2 openscad

To make the setting permanent, add export QT_QPA_PLATFORMTHEME=gtk2 to your user's ~/.profile

我在Ubuntu系统中运行OpenSCAD时并没有看到菜单栏，怎样才能让她回来？

This seems to be caused by Ubuntu messing with Qt to move the menubar somewhere else (e.g. top of the screen).

That problem hits other applications too, see https://bugs.launchpad.net/ubuntu/+source/appmenu-qt5/+bug/1307619

There are two things that could help:

• Set the QT_QPA_PLATFORMTHEME environment variable to an empty string (the default value is probably "appmenu-qt5") or simply run OpenSCAD with QT_QPA_PLATFORMTHEME= openscad
• Remove the appmenu-qt5 package to globally disable menubar changes for all applications

为什么程序给出的错误行号是错的？

That is a limitation/bug in the current parser that handles include<> basically as copy&paste of content. In some cases it's possible to work around the issue by placing the include<> statements at the end of the file.

When depending on libraries, it's recommended to use use<> instead which does not have that problem and also automatically inhibits any top-level geometry of that file (which might be there as demo for the library).

我不喜欢OpenSCAD自带的编辑器，我能用我最喜欢的编辑器取代她吗？

Yes, OpenSCAD supports a special mode that will reload the files if they are modified externally. To enable this mode, check the Design -> Automatic Reload and Preview option and just close the editor window (or use View -> Hide Editor).

As an example, here's a script which runs vim as editor and also starts OpenSCAD which will take the model viewer role.

It supports 3 modes

• Run with no parameters, it opens a temp file for quick testing, which it deletes.
• Run with the name of a non-existent file, it starts the file with a default license header.
• Run with the name of an existing file, it simply opens it.

#!/bin/bash
  
FILE="$1"
AUTHOR="Your Name Here"
YEAR="$(date "+%Y")"
LICENSE="// Created in $YEAR by $AUTHOR.\n// This work is released with CC0 into the public domain.\n// https://creativecommons.org/publicdomain/zero/1.0/"

# increase stack size to allow deeper recursion
ulimit -s 65536

if [ "$FILE" == "" ]
then
  TEMPF=`tempfile -s .scad`
  openscad "$TEMPF" >/dev/null 2>/dev/null &
  vim "$TEMPF"
  rm -f "$TEMPF"
  exit
fi

if [ ! -e "$FILE" ]
then
  echo -e "$LICENSE" >> "$FILE"
fi

openscad "$FILE" >/dev/null 2>/dev/null &
vim "$FILE"

Errors / Problems

为什么我会收到"no top level geometry to render（没有可用于渲染的顶层几何体）"这条消息？

This can have different reasons, some common ones include

Missing / Commented out module call

module model() {
  cube(20);
}
%model();

Using the % modifier does not only make the part transparent, it's not included in the final render!

Difference / Intersection with wrong translated objects

The easiest way to solve this type of issues is to highlight the objects using the # modifier and see if the objects are placed at the position where they should be.

Importing broken STL files

See Why is my imported STL file only showing up with F5 but not F6?

若OpenSCAD崩溃或被强行终止运行，我未保存的资料会丢失吗？

Before starting a preview or render process, the OpenSCAD editor writes a backup file in case there are unsaved changes.

This file is stored in the users documents folder in a separate directory (e.g. on Linux this is normally $HOME/.local/share/OpenSCAD/backups). The actual path can be checked in the Help->Library Info dialog where it is listed as "Backup Path".

在Windows上点击"New（新建）"或加载文件时，OpenSCAD奔溃惹

在部分装有Intel图形驱动的机器上OpenSCAD会崩溃，至于更多细节，请参见https://github.com/openscad/openscad/issues/2442

报告bugs、申请功能等问题

我该怎样报告bugs？

Bugs in OpenSCAD are best reported in the github issue tracking system at https://github.com/openscad/openscad/issues. If you are not sure it's a bug, asking on the mailing list/forum can help clarifying things.

Please try searching through the existing issues if the bug was already reported. If you find something similar or if you are unsure, create a new issue, but mention the (possibly) related one.

The bug report should give as much information as possible to help with reproducing it, including but not limited to

• The OpenSCAD version
• The Operating System name and version
• A description of the scenario that produces the issue
• In case of graphics issues, the OpenGL driver information
• If possible, a trimmed down script reproducing the issue

Most of the technical version information can be found in menu Help -> Library Info.

我该怎样申请新的功能？

New features or changes/extensions to existing features can be requested in the github issue tracking system at https://github.com/openscad/openscad/issues too.

Please make an effort to clearly explain the new feature / change as detailed as possible. Including some background about why you think this feature would be useful to you and other people helps a lot and increases the chances of it being implemented.

怎样按我所用的系统来报告OpenSCAD中存在的bugs？

Windows

The Windows version is currently maintained by the OpenSCAD team, so please use the github issue tracker for reporting bugs.

Mac OSX

The Mac OSX version is currently maintained by the OpenSCAD team, so please use the github issue tracker for reporting bugs.

Linux

The OpenSCAD versions included in / distributed by the various Linux distributions are usually maintained by people/teams working with the distributions.

Specific bugs can be reported in the respective bug tracking systems, e.g.

• Debian - See "please report it" directions at https://bugs.debian.org/cgi-bin/pkgreport.cgi?package=openscad

• Ubuntu - See "Report a bug" directions at https://launchpad.net/ubuntu/+source/openscad

• Fedora / Red Hat - See https://apps.fedoraproject.org/packages/openscad/bugs and https://bugzilla.redhat.com/buglist.cgi?component=openscad

• Arch Linux - See "reporting bug guidelines" directions at https://bugs.archlinux.org/index.php?string=openscad&status%5B%5D=

The nightly builds hosted on the openSUSE build service are maintained by the OpenSCAD team, so please use the github issue tracker for reporting issues with those packages.