OpenCADSolutions

Peter Uithoven - Open CAD solutionsOpenCAD solutions:FreeCAD:

OpenSCAD:
  • Download:
http://www.fablabamersfoort.nl/nl/book/openscadFreeCADbasics
  • Start with a workbench selection for what you want to do.(view -> workbench)
  • Start with the "part design" workbench.
  • Part design starts with a 2D sketch.
  • In Part design you can set constrains, like "this needs to be straight" and "these needs to be parallel".
  • In the "part" workbench you can work with 3D shapes
  • Moving components in 3D view is very hard and needs to be done in the "data" tab at the bottom let, at "placement"
  • To create an .STL: go to "Mesh", give a tolerance (e.g. 0.1) and this gives you a new Object "Mesh"
  • Navigation: if you used to a certain 3D navigation (e.g. Blender), you can change that in the preferences
It's not really production ready:
  • For instance, It's not very easy to move things: in "Draft" you can move things (but doesn't seem to work in every version and OS)
  • Sketch-View: You can not copy stuff and there is no way to create components (e.g. a screw that you copy several times - and if you change something on the original screw, the copies change as well)
ComboView via view->views->comboviewOpenSCADimport from inkscape:
in OpenScad, type: 
linear_extrude(file = "filename.dxf", height = 5, center = true);
Hints
  • Press F5 (on Mac: fn+F5) to update the view
    • You can also use an external editor: (later)
  • Modifiers: 
    • //: comment out: this line is ignored
    • #: to see the shape behind it
    • !: only show this part (or do this action)
    • %: makes the shape transparent and ignored
    • *: everything after the star is ignored (not just the line, but until the next ;
  • you can define variables in a module, but only at the beginning, not afterwards
  • you can export the file for instance to DXF and open it in inkscape (for instance to add a nice font or hand-drawing)
  • using another editor:
    • open the file in another editor
    • in openSCAD set Design>Automatic Reload and Compile
    • voilà
Limitations
  • you can not create lines
examples
  • cube(10)
  • cube([10,20,30])
  • translate([10,0]){
  • square([10,10])
  • circle(5);
  • }
  • translate([10,0,0]) rotate(45) square(10);
  • functions:
  • module shape()
  • {
  • translate([10,0,0]) 
  • {
  • rotate(45) square(10);
  • }
  • }
  • shape();
  • translate([-20,0]) shape();
  • square(2);
  • Boolean operations
  • difference
  • difference{
  • shape();
  • translate([6,0]) shape();
  • }
  • Intersection
  • Union
  • variables
  • width=100;
  • x=10;
  • cube([x,width,10]);
  • Extrusion
  • linear_extrude(height=20, twist=50) square([10,20]);
  • Inclusion of external parts
  • include
OpenSCAD has the limitation that it only can create 'solids': it can creates 2d circles and squares but not lines. If you make a very thin rectangle a lasercutter will still follow the outline of the rectangle. May a simple postprocessing script can replace thin rectangles by lines in the DXF.
MCAD library
Other
  • you can do animations (example of the spiderbot, link?)
Few simple examples: Inkscape
Set the default units to mm in the document properties
It's possible to draw a shape and then set the specific x, y, width, height in the menu.
Keep in mind: you enter the top left position of circles 
OpenSCAD can't import curves so you have to convert them:
- select them
- extensions -> motify path -> add nodes
- select all
- press button: make segment lines of it 
- save as dxf desktop plotter 
Plugin to make this easy:
http://libregraphicsworld.org/blog/entry/inkscape-gets-openscad-converter
[please check]
Making clones
edit -> clone 
In OpenSCAD you can then make it 3D by extruding it. 
Using linear extrude you give the 2D shape a height. 
Using rotate extude you can do revolutions
My notes: http://companje.nl/inkscape
LibreCAD (based on QCAD?)
  • 2D CAD program
  • nice user interface
  • toolbar on the left changes based on context, really good!
  • Not always very intuitive
PyCad
  • very basic
  • too basic to be usefull yet
  • "don't use the tool, it's not very useful at the moment"
K3D
  • looks nice, you can connect variables of different objects
Writing SVG files by hand: A parametric SVG editor by FabLab Amersfoort
  • example
  • size=100
  • dist=0.2*size
  • mood=1
  • x=105
  • pretty basic, but very nice and useful to generate small SVGs
  • can do things, that OpenSCAD can not do, e.g. lines
JS Bin
Writing svg elements in JavaScript
http://jsbin.com/ehayep/71/edit
this is also possible in open scad
BRL-CAD
.

      make sure you have no bent lines (curves), export as .dxf type 13

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