Sketchup 3D printable objects tutorial

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Introduction

Google sketchup is currently probably the easiest 3D modeling program. It can be used to create simple 3D models for printing with a 3D printer like the RapMan

Prerequisites: Know how to print with a RapMan (or similar)

See also: Skeinforge for RapMan and Meshlab for RapMan tutorial

Tools needed

(1) Download Google SketchUp. We will work with the free version. The professional version not only has more features, but also could export directly to .OBJ which then can be imported to skeinforge.

(2) Download MeshLab. We will need this to convert SketchUP output to the .STL format.

(3) Download netfabb (free Studio version). This is needed to fix the STL file.

(4) Download Skeinforge. This can import STL and generate the g-code. Note: A next version of netfabb can do this too. Also read the Skeinforge for RapMan article !

Sketchup basics

Settings and concepts

Startup

Select the template: Product and Woodworking

Configure the Interface

The interface can be configured:

  • Select Menu: View->Toolbars->Large Tool Set
The Axis

The push/pull tool with an example

The Push/Pull Tool allows to push and pull faces to add volume to or subtract volume from models. E.g. you can use this to print name tags for your luggage or gift tags for the first rapman pinguin you made.

The idea of making holes with letters comes from Gift Tags by Roboteernat.

This is fairly easy to produce:

A name tag made with Rapman

To create a small solid cuboid (3D rectangle):

  • Zoom in a lot (mouse wheel) and make sure that you can see the origin (use the hand tool to drag)
  • Select the rectangle tool: Draw a rectangle by clicking to a first point, dragging and then ckick/releasing the mouse. Make it about 60mm long at least and 1.5cm high at least. Letters should be at least 1cm (otherwise print may fill in the holes)
  • Select the Push/pull Tool: Click on the rectangle and move up (about 5mm)

To create a a void (empty) space:

  • Principle: Draw a 2D shape on a 3D geometry (e.g. the cuboid above) and then push until it is "on face", i.e. exactly meets the back end.
  • Now make a hole with the circle tool.
  • Select the Push/pull tool, move over it the circle (it should high-light with blue dots). Now push it down (slowly!) until the tool says "on face". Release the mouse and you will see a hole.

Select the 3D text tool

  • Set height to 100mm (at least)
  • Select an ugly regular font and make it bold (e.g. Arial)
  • Tip: with the webdings font you can add a heart ("Y")
  • Untick extruded (letters must remain 2D)
  • Set form filled
  • Click "Place" and place it on the rectangle (make sure it's "on face")
  • Right-click (object must be selected) and explode
  • Optional: space out the letters (will give a better print)
  • Push each letter down as explained above. This is a bit tricky, tilt the object (e.g. to a 60 degree angle) and zoom in (else you can't select the letters). Make sure to push util the tools says "on face" !

Export as Collada

  • File->Export->3D Model; Select Collada

Sketchup to STL to g-code

Two strategies

Since the free version of sketchup doesn't allow you to export directly to .STL, there are two options:

  1. Export to Collada .dae (a known 3D file format for exchange) and then import to a tool that can translate .dae to .stl
  2. Install a plugin, e.g. Convert Sketchup SKP files to DXF or STL

We will show here option 1, i.e. use Meshlab to translate Collada to *.STL.

  • Open MeshLab and import the Collada .DAE file
  • You should see the object from the top (z axis is forward/backward)
  • Export to .STL

STL to g-code

The .STL or the Collada export is not necessarily great for printing, the resulting STL may not be correct, i.e. won't print for various reasons.

Also, size may be wrong, e.g. when we imported the object we made above to NetLab, the object was ok, i.e. not fixing was needed, but it shrunk to very small. ...

  • Repair by clicking on the red + sign (I just used default repair). Apply the repairs.
  • Leave the object near x=0 and y=0 (the rapman 0/0 is in the middle!)
  • Export the fixed .STL code

Now print

  • Import the fixed .STL to Skeinforge and generate the g-code (see the Skeinforge for RapMan article !)
  • Print ... :)

Empowering Sketchup

The free sketchup version can be much enhanced with so-called plugins. To install a Plugin, copy its files directly to the sketchup plugins directory, e.g c:\programs\google\google sketchup 7\plugins. You then will see changes to the interface of Sketchup when you restart the program.

To find good plugins:

I got:

  • Join push / pull (to extrude several objects, found in "must have Ruby plugins")
  • JS Align - align along 1 of the three axis (found through Search in the education forum)
  • A surface tool plugin (allow to draw on curved surfaces, found in "must have Ruby plugins")
  • The 1001bit tools (quite amazing tools for building houses, but also for layouting)

Links

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