?Best? transportable CAD file format?

[vladdy]

I realize that there may quite a bit of 'difference of opinion' on this, but..
was wondering what were the 'better' formats of cad files to use to get better transportability between different cad and / or cam systems..
I 'personally' like inventor to generate the cad files, but it seems not very many cam systems like ipt formats,
most [that I have seen anyways] cam programs prefer IGES , SAT or SolidWorks formats..

opinions anyone ??

[tjones]

I was told by a long time user of Cad and Cam software that iges is going out and step was in. Not sure if that $.02 is worth much but I personnaly have better luck with step file formats than any others in Cam software.

Check out Alibre Design. You can download their Xpress version for free but it has no exports unless you pay for the $99 Export module. With the module it can import and export many formats like dwg,igs,stp and rhino.

Very nice compared to those high cost software. There will be things you will like worse or even better than your current software. The point is the free version has limits but it is free.

[vladdy]

I have quite a few choices with inventor for what format to save / export to,
including iges, sat, step, stl, as well as native formats..just not sure which format is more 'universally acceptable'..
The reason I ask is that I have thrown most of the ones I've generated, as well as other interesting samples off the net onto my personal web page for others to use if they wish..
I still haven't finalized on what I personally will use for a CAM package, and it seems that most CAM software offerings have an individual preference as to the format that imports best in each case..

thanks

[DareBee]

Considering most people are into MCAD I would thing that parasolid would be about the best for transfer.
Stl is pretty well gaurenteed to work because everyone supports 3D printing these days.
Going back to oldschool I do personally prefer step over igs.
In 2D Acad has been a standard for so long that I believe more programs accept straight dwg than dxf's anymore ,lol.

[imserv]

Parasolid, SAT, and ACIS are proprietary formats and you are almost guaranteed that there will be problems between dissimilar systems.

DXF is an autocad format that was developed to facilitate drawing interchange. It is the most popular for 2D drawings. It can be used for 3D surfaces, but also uses an ACIS derivative for solids and hence is not as useful for communicating complex assembly designs. DXF does change from time to time as Autocad adds new capabilities, but over the long haul is fairly stable.

DWG is the Autocad database and is not publicly released. There has been a major effort by Autocad's competitors to reverse engineer DWG and interface to it. However if you watch how things work, every year or so there is a scramble as all the opendwg alliance partners scramble to reverse engineer the latest Autocad DWG enhancements.

IGES is a portable drawing format that has been around for many years. It is a standard (Initial Graphics Exchange Standard) and problems are usually associated with how complex nurbs surfaces are handled, not simple drawing elements like lines, arcs, splines, dimensions,etc. The file definition includes both complex 3D entity types and simple 2D elementals.

STEP is an outgrowth from the iges standard. The CAD portion is based on IGES. It has other things included to supposedly cover manufacturing process and product life cycle management. It is still a work in progress and may stay that way for a long time.

STL is a specialized 3D surface/solid developed for Rapid Prototyping machines. It is not useful for anything but surface data. No accurate 2D data ( like arcs ) or dimensions are included in STL files.

Rhino 3Dm files are based on a published open standard for NURBS based surfaces and also 2D elementals. Because Rhino3D is popular and it is an open standard, many Cad-Cam programs have incorporated it. If the Cad program has poor NURBS handling, this format will have the same problems as IGES or STEP with surfaces.

Fred Smith - IMService
http://www.cadcamcadcam.com/hobby