OpenSCAD Seminar

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Seminar on "Parametric modeling with OpenSCAD" by Mitja

We will give an introduction to parametric modeling and design a few things with OpenSCAD.

Basic Control

Have a look at OpenSCAD's user manual for more information and specific functions!

  • type into the editor on the left
    • whenever you are ready to compile your code to see it in the 3D preview on the right, you can click "preview" or hit F5
  • group arguments with { ... }
    • group objects by applying union() to a group of arguments - important for CNC!
  • subtract objects or groups of objects from each other with difference()
    • everything is subtracted from the first object or union after this function
  • ! at the beginning of a line shows only that operation
  • # at the beginning of a line shows that object as defined, e.g. also the superfluous parts of a hole

First Steps

We start by defining a small cube (units in mm) with cube([2,2,2]);.

  • center the cube by adding center=true after the vector, between ] and )
  • translate (move) the cube by calling translate([2,0,0]) - it will end up two mm further in positive X direction

After also tinkering with some spheres and cylinders (enter $fn= followed by a number to define your desired face count, high numbers increase rendering time!), let's move on to parametric designs.

Parametric Designs

We'll make an "L" with adjustable side lengths and a parametric hole.

The "L" is rather simple and consists of two "cubes" that are actually rectangles due to the entered values. By adding the global variable "edge_length", we can later change the dimensions of the entire letter while keeping its proportions:

edge_length = 5;

union()
{
    cube([1*edge_length,5*edge_length,1*edge_length]);
    cube([3*edge_length,1*edge_length,1*edge_length]);
}


Then, we add a hole with a corresponding "hole_diameter" variable and turned the L into a module which can then be called similar to cube or sphere from the first examples:

module L(edge_length, hole_diameter)
{
    difference()
    {
        union()
        {
            cube([1*edge_length,5*edge_length,1*edge_length]);
            cube([3*edge_length,1*edge_length,1*edge_length]);
        }
        translate([edge_length/2, edge_length/2, -1])
        cylinder(r=hole_diameter/2, h=edge_length+2, $fn=20); //sticks out 1 mm at top/bottom, "centered" in corner
    }
}

L(4,1);
translate([15,0,0]) L(6,2);
rendering resulting from the code above

The last two lines in this example create two "L" shapes with different sizes, one of which starts at the origin while the other is moved 15 mm in X direction.

Uploading to Thingiverse (Customizer)

Uploading the design to Thingiverse is easy, just click "This is a customizer" in the process and the app will automaticall parse your variable names and the associated comments. Make sure to comment precisely and understandably so others enjoy your customizable creation!


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