Stereo lithography examples?

[Francois Levy]

I'm wondering if anyone on the list has exported a Vectorworks model to STL and output to a 3D printer. If so, I'd like to hear about your experience.

[GWS]

Hi Francois,

I have exported the attached file to STL and then 3D printed it. It all worked fine, except that the grey surfaces would not read as a solid. (I have cut away half of the surfaces to show that they are hollow).

I could not find a away to get them to be read by the 3D printer as a solid. I eventually imported the STL into 'Inventor' which read them as a solid and then exported again to the printer.

I have used other files with great success but every now and then VW doesn't quite join the dots.

HTH

Edited December 18, 2009 by GWS

[rDesign]

The Mac OSX application 'topeScope might help diagnose those STL problems (and the paid Plus version at $145 USD is much less expensive than Inventor).

The demo version functions as a free STL viewer, so you can at least see if there are problems with the VW export.

Regards,

Tim

[GWS]

Thank you Tim, I'll give it a look

[Kurt Magness]

Not sure if you figured out STL export to 3d printers yet. But I will go through some things in case future people have questions. Vectorworks actually works very well. You just need to know the capabilities of 3d printers and the limits to the STL file format. I have been building architectural models for a while using Vectorworks and the STL process .

A couple of things to note:

3d printers (rapid prototype machine or RPM) printers are very picky about the files.

STL files can get funky and most always need to be repaired prior to being sent to a RPM machine whether they come from Vectorworks or other programs. The STL file turns everything into a series of connected triangles.

The model might look great in Vectorworks but the STL exported version may be all messed up. You need a STL viewer program to see what you really got. Also STL errors are not readily visible. It may visually look ok in a STL viewer program but still be unbuildable. Flipped faces, duplicate faces, anti faces, holes, unreferenced vertices, etc. You need to run the repair program or pay someone to do it.

Some RPM service bureaus are more helpful than others. Some can repair files, some will just say its unbuildable.

In Vectorworks you need to have all the info on one layer prior to attempting a STL export.

You need to have the part thickness be build-able. Here is an example: if you are modeling a building, a 6" thick wall, depending on what scale the actual model will be, may be too thin to build. I typically build models at 40th scale and make my walls 3 ft thick. Look at the 40th scale on a ruler. 3 feet at 40th is really less than a 1/10th of a inch thick ! Any part less than a 1/10th will sag, warp, be too fragile, etc. depending on what it is. Remember the RPM machines basically layer up the parts like a ink jet printer spitting out glue over and over to get thickness.

I use the cased opening setting for all my doors and windows . If you have mullions, jambs, stiles, trim etc., the machine will try to build them and if they will not resolve into build-able parts (ie too thin) the machine may not read the file correctly.

If you attempt to STL export a file of a building that is say 100 ft x 100 ft x 40 ft high, the RPM machine will not be able to read the file correctly because it will try to build the model the real size !

STL files need to be at 1:1 scale. So for instance the 100 ft x 100 ft x 40 ft high building really is about 2 1/2 " x 2 1/2" x 1" in 40th scale, model size.

I use 'topeScope to view, repair and reduce the scale to 1:1

If you try to scale a complex, multi story, architectural building in Vectorworks all the doors & windows will get messed up.

'topeScope is the only Mac STL viewer and repair program. There are others for the Windows platform. 'topeScope is well worth the price. The guy that wrote it is way nice and doesn't sell too many versions. It started out as freeware. Most RPM service bureaus are Windows based and use a program called Magic.

There are several different processes for RPM machines depending on the resolution you require. Polyjet, FDM, etc. RPM machines have a maximum build bed. Most are only 12" x 12" x 6". So models need to be split up into sections if you want them bigger.

The process is very expensive and is priced by volume of material not necessarily the complexity of the model. I just got a quote for a 5" x5" x 2" model $900 for the smoothest process (polyjet) and $500 (FDM) for a lesser smoothness.

I get parts laser cut like site plan stuff, roads, walks, etc. Way cheaper, just DXF export 2d files at the correct, actual scale.

I have more tips and suggestions if you want email me: magarc@mac.com or visit my web site kurtmagnessarchitect for examples.

Edited February 24, 2010 by Kurt Magness

[Benson Shaw]

Excellent info, Kurt. Thanks!

-B

[Stanley Rostas]

We can confirm the need to repair STL files no matter the application exporting. Their are many apps to perform this work but we have relied on the print houses to do the cleaning.. Closed polygons and flipped faces are a curse.

[ColinW]

I export stl files from VW and import into Meshmixer to check before printing, it's a Mac and Windows app which is free and popular with the 3D printing community for repairing stl files, mixing stls together and modifying them. It's was acquired by Autodesk who seem to be taking it's underlying technology and adding it to fusion360, but it is still free and still one of the go to apps, search youtube for videos showing how to repair stls if you want to find out more about it, I found the Makers Muse Youtube channel very accessible.