Choosing which filetype to use ? STL or AOI ? or OTHER?

Hey guys, Im just getting into this whole Rep Rap project but need a little advice. Before i start my rep rap i would like to know which filetype is most user friendly and editable! I would like to take the Prusa Mendel model files and create 2D drawings of them with dimensions. This is for my own use as In time i hope to reproduce the Prusa Mendel printable parts out of cast alloy. Ok i realise this goes against the self replicationg theme but its one i would like to explore none the less but I will need the parts dimensions before i can do this ! So what I need to know is What filetype will contain the actual dimensions for the parts. Im guessing they all do ! Second what software will allow me to read and edit the filetype in question and third will the choosen software package allow 2d prints of the 3d object like viewports in autocad ! or do i need to redo each model in a seperate 2d cad package ? Finally can SketchUp read any of the filetypes currently in use ?

OK I know thats a lot of questions but im very new to this area and have only just begun my own research which progresses as normal ! ie when time and the wife allow

There are several parts to the equation

In general, One designs in cad, then exports to a file format suitable for path generation, whose output is sent to a final program which is used to control the printing operation.

In terms of what one uses to design a part, that's dictated solely by the choices you make and can afford. Some use free programs like Sketchup, Autocad123 (or whatever they're calling it now), Blender, OpenScad, FreeCad, etc., while others opt for purchased programs like SolidWorks, Autocad, Alibre, etc.

STL is, as far as I know, used by the majority of reprap folks for the input file type for extruder path generation, so a design program probably ought to support exporting of stl, at least for now.

Path generation is handled by programs like Slic3r, Skeinforge, and others

Finally printer interfacing is accomplished using programs like Pronterface.

I have not noted all the possibilities, nor fully explained *all the details, just enough to roughly illustrate the basic issues.

The single "universal format is, afaik, what goes to the path generation software, so make sure you can export to STL or choose the various elements wisely so that you can go from design to print.

Edited 1 time(s). Last edit at 02/23/2013 08:48AM by xiando.

OK that makes sense and has made things soo much clearer for me now. Now what I would like to do is to take a STL file and import it into a CAD package to assess the dimensions of the model. Is this possiable at this time ?

EDIT: yes.

If I'm not mistaken, all of the CAD packages I've noted above either integrate STL importers directly or they can be added on. Someone else will have to confirm for packages I don't use or can't use. (I use Sketchup and both import and export are free addons)

I would note that for the fullest import of a fundamental design, STL is not ideal, since native CAD info is lost during conversion. So, for instance, if you owned a license for Solid works and were given the option of downloading a design in STL or Solidworks format, you'd probably want the Solid works file. But if you don't have direct access to the native source code, then STL represents a defacto "universal" source, even if it isn't as fully featured as the native format for a given package.

Edited 2 time(s). Last edit at 02/23/2013 01:15PM by xiando.

OK . Again many thanks. I enjoy the simplicity of Sketchup 8 and have used and retain many of the earlier versions. I also use Blender and AutoCAD for more complex designs amongst other Packages I merely dabble with !

So what i now need is the actual CAD models first released for the Prusa Mendel or the most recent edits. This would allow me to then either use the propritery package to read display the models or possiabally convert the models into a format that can be used by the packages I use. From there I hope I can generate 2D Drawings of the parts or if I have to simply record the dimensions and then redraw themn in a 2D package. This, and a better understanding of how it all works, is what I hope to achieve today.

Are you aware of where I may obtain accurate CAD models for the prusa mendel ? SKP format would be fine but am happy to use any sourse thats freely available.

I'm not aware of skp for the mendel. I've only downloaded STLs at thingiverse for various components. The various reprap wikis may also contain suitable files.

So the short answer is I don't know. Thingiverse, wiki...that's all I can really offer.

Many of the reprap developers have .scad files and similar on their github, and sometimes on thingiverse too.

Edited 1 time(s). Last edit at 02/23/2013 06:25PM by xclusive585.

RocketMan2013 Wrote:
-------------------------------------------------------
> Are you aware of where I may obtain accurate CAD
> models for the prusa mendel ? SKP format would be
> fine but am happy to use any sourse thats freely
> available.

Here, both .stl and .scad files are available. You will need OpenSCAD to render .scad files, to view them, you can use almost any text editor, its just plain text.

You could try the latest version of FreeCAD to convert the scad files, but its still a bit experimental and the
the underlying OpenCASCADE that it uses has bugs with some files.

Best to break the scad file into parts using a text editor and try the parts separately
i.e. edit scad file to just produce one part. Test it still loads okay with OpenSCAD
then Import with FreeCAD

Having imported the scad file into FreeCAD you can then export to STEP, IGES, native FreeCAD
and edit in your favorite 3D CAD software

see http://www.sloan-home.co.uk/ImportCSG/ImportCSG.html for more details
see also http://www.youtube.com/watch?v=UXCP-p4Y3hM&feature=uploademail

Note: you do have to tell one time FreeCAD where OpenSCAD is. see
https://sourceforge.net/apps/mediawiki/free-cad/index.php?title=OpenSCAD_Module
https://sourceforge.net/apps/mediawiki/free-cad/index.php?title=OpenSCAD_AddOpenSCADElement#Initial_set_up_from_within_FreeCAD

If you are trying to produce a 2D DXF file, then there is an out of date tutorial at
http://www.youtube.com/watch?v=GFuyF78QLGc
covering how to produce a 2D view from a 3D model in FreeCAD.

Having produced the 2D view you should in theory be able to export as a 2D DXF file.

Edited 4 time(s). Last edit at 02/24/2013 05:06AM by KeithSloan.

If you do go down the route of using FreeCAD to convert the scad file then it is worth checking that FreeCAD
converted the file okay.

Go to OpenSCAD workbench
View | workbench | OpenSCAD

Then use icon "Anaylze Geometry for Errors" Its the cone with a magnifier at the top.
If there are errors you can then try and fix them with some of the other icons like refine shape.

In any case please report any problems in the FreeCAD forum https://sourceforge.net/apps/phpbb/free-cad/ So that problems can be addressed in the future.

If you can supply a small problem file ( i.e. just one part ) that would be great. NOT a file of a COMPLETE RepRap
as these are really too hard to debug.

Some known problem scad files from thingiverse are documented here https://sourceforge.net/apps/mediawiki/free-cad/index.php?title=OpenSCAD_CSG_tested_files

So yeah, as you can see, there are a variety of native source files available, Some authors post their designs in whichever native format they work in, some provide both their native format and something that most folks can at least print and import (STL)

Probably the best bet if you're attempting to get as many files in their most original format is to download (and when necessary purchase) and install as many of the CAD programs listed in the wiki as possible. Obviously, unless you're filthy rich or a software pirate, you're not going to have ALL of them (purchase price for Solid works, Autocad, etc can add up very quickly), then import STLs or other potential imports when your ability to load native fails.

Trouble is STL is a Triangulated Mesh format. It has its limitations if you want to redesign something. Fine for printing though.

KeithSloan, true enough. My point was simply that it is the most universal format available at present. And push comes shove, if stl is the only thing available, then at least one can print and although not ideal, import it and work from the files within many editors. Not nearly ideal, but far more so than encountering designs that only offer files one can neither open nor use to print.

Obviously, as should be self-evident from my bolded text in the post above yours, I believe that covering the bases is a best option. Eggs in one basket tend to limit.

Well if I am correct the original request was to take a prusa design and create some parts as 2D drawings. It seems prusa is available in stl & scad formats. With stl you could import it and construct a 3D model around the stl object using it as a pattern and then create a 2D view from the 3D object. But to me its a tedious process and not necessarily going to be 100% accurate. With scad files you can create an stl from OpenSCAD. The other option with a scad file is to try and use FreeCAD's scad import facility. It might work it might not as there are limitation. I would not try it with a complete Reprap as the limitations are almost bound to come into play. If you do it with individual parts then if it does work you have gone to an accurate 3D model and then can use FreeCAD to create a 2d drawing and its not a lot of manual operation.

One option is of course to print the part and then draw it from scratch in 2D again how accurate it that going to be?

I would give FreeCAD a try. but then again I am biased as I wrote admittedly with some help from Sebastian Hoogen the OpenSCAD CSG importer and exporter, which are now part of the FreeCAD OpenSCAD module

If he can get all the original files for the design in question in another cad format, great. Had you read my replies to him, you would know that I said as much already. Further, I was not trying to score political points by promoting a specific cad package, which, in my understanding of the origins and spirit of the open source movement and one of its children, the reprap project, would be contrary to such an open-ended general set of questions such as the OP's..

Here: let me quote it so you can continue your game using something you'll actually have to read in order to respond:
I'm not aware of skp for the mendel. I've only downloaded STLs at thingiverse for various components. The various reprap wikis may also contain suitable files.

So the short answer is I don't know. Thingiverse, wiki...that's all I can really offer.

I can translate it to your native language if you don't comprehend the content of the above quotation as written in plain English.

In contrary to your stance, I gave him as much information as I knew that would give him a fundamental background on the file/cad scheme that is being employed by all the various players in the Prusa Mendel style and variant hot extrusion printing, including the single somewhat universal "language" that makes the tower stand. I understand and respect that some wish to tear it down and speak in many tongues. You've made your point.

xinado If you knew anything you would know that Prusa is only available in stl and scad format.
As was confirmed and pointed out by miso, you did read his post didn't you?
Its Mendal RepRap that is available in various formats for example at http://www.3dcontentcentral.com

But as you said "So the short answer is I don't know. Thingiverse, wiki...that's all I can really offer." If you don't know then why make all the fuss and noise? If I read your posts and don't think they are contributing anything then I feel it is quite
okay to ignore them.

I was trying to point out that there are potential options with scad and FreeCAD and these posts were aimed at Rockman2013 who raised the original requirement to create 2D drawings not you xinado.