Tuesday, 13 October 2009

Open-Source to the rescue!

To build anything in a RepRap, you need to have a 3-D design, save it as a STL or triangle mesh file, and load it into the RepRap host software (or skeinforge).

To create these designs, RepRappers use different programs - Either an adapted 3-d modelling programs, originally used for animation (like Blender and Art of Illusion), or freeware versions of CAD software (like CoCreate). These solutions work, and work well, but each program has seperate advantages. I've been looking out for a 'better fit' - a CAD-style program, that supports building meshes and solids.

Make magazine today furnished me with a link to FreeCAD.

It's pretty slick - either I'm quite lucky, or it works quite well. Within a few minutes I was able to load it up, get started, create a small cube model, export it to an STL file and import it successfully into the RepRap Host software (not always an easy thing!).

OK, lets give it a real test...

Let's load up some data from a complex file: a human head.
To really test it, I created a large sphere, stuck it on top, and did a 'union' (Join).
This is not nice: most complex geometries cause all sorts of bent and broken and backwards triangles. Lucky there is an analysis tool to point all this out:
From FreeCAD

Pressing some of the 'repair' buttons sorted all this out.
From FreeCAD

This exported easily to an STL file: and then loaded straight into the host software.

From FreeCAD


It started to slice and print to gcode : it got to 55 layers through before I got bored and turned it off.

FreeCAD is currently alpha software so far, but certainly one to watch!

3 comments:

Erik de Bruijn said...

Wow, Thanks for pointing me at FreeCAD again. I had tried to get HeeksCAD to work in my search for open solid CAD software, but it seemed that no mature project existed. This is alpha but already very usable. Having more programming than CAD experience, I love the scripting capabilities. I just generated a bottle.stl based on specifying dimension to a user script that could output the STL file.

BodgeIt said...

Very interesting Thanks for the link.. will give it a try.
I do have to ask did you read The Egale comic ?
Your head looks remakably like the Mekon from Dan Dare.

Renoir said...

I suppose my head is rather large... it's not green, though.

Oh, you mean the 3d model...

:-)

I used to read the 'Eagle' - Also, I played 'Dan Dare' for hours on my spectrum +.