|
upFront.eZine |
|
|
a
publication from |
|
|
Issue #576 : : October 14, 2008 |
|
|
In this issue:
- The Single Part Problem |
Write the editor. Make him smile! Through Paypal, consider donating $25 in support of upFront.eZine. Or else... We're trendy. We have a Weblog. WorldCAD Access. |
|
|
|
|
On the way to last month's Vectorworks Press Event, I shared the airport shuttle with David Shook, sr vp of Americas for Siemens PLM. He's been with some form of the company since 1980; he remembers when legendary CAD editor Steve Wolf reviewed in the first issue of his newsletter the software Mr Shook represented. As the shuttle bus driver detoured to avoid a freeway traffic jam outside Baltimore, I asked Mr Shook thought might buy PTC. He hoped it would be Oracle, for then Siemens PLM would have little to worry about. Cyon Research's Brad Holtz thinks Oracle turned down the opportunity. Sounds like the chaos-is-normal world Seth Godin speaks of (see Notable Quotable, below). - - - Over breakfast, a Vectorworks employee wondered what might be the Big Thing in CAD. Editors sitting around the table looked at each other, and I finally ventured parametric CAD as the last big thing; it came out 20 years ago. Brad Holtz thought -- he asserted -- that it was synchronous technology. I countered that synchtech was too new to know whether it would become the Next Big Thing. - - - During an interview with Rix Kramlich, vp of worldwide marketing and business development at Right Hemisphere, he asked me what I thought the hot issues were in CAD. In the area of MCAD, this year it's expansion away from traditional metal-based design, and into plastics, electronics, fluids, and other "squishier" materials that are harder to simulate with software. Next year, someone might figure out the CAD equivalent to Google Docs. The closest I know of in the CAD world is Autodesk's Project Draw; Dassault's V6 might be more like it, but they are keeping their marketing too sparse for me to know. (Not that vendors haven't tried before online CAD before. Alibre began as a Web server-based MCAD program; it now runs locally but with an optional repository in the cloud. Autodesk briefly ran AutoCAD on its servers, while back in our offices the software jerked and snagged its way across our screens. Dassault is trying it now with its current V6-branded software.) Perhaps a Chrome-like approach is needed, where the Web browser acts as the runtime environment to provide the speed CAD needs, while the Web provides continuous updates, realtime back up and storage, instant collaboration, and effortless remote access. OpenRP: Solving STL Problems
The STL [stereolithography] format is the standard file format used by the Rapid Prototyping industry. Almost all solid modeling software has the ability to save 3D data to STL files. STL files are of two types: ASCII and binary, the latter being preferred due to its smaller size. But, the STL format has serious drawbacks, which can be overcome with the new RPX format
The Single Part Problem The creators of the STL format designed it to define a single part, not an assembly of parts. ASCII STL files start with the keyword 'solid' and end with the keyword 'endsolid'. Between the two keywords is a collection of 'facet' information that describes the triangles of the mesh model. (To see this, you can open an ASCII STL file in NotePad.) This limits an STL file to holding just one solid object. To store the geometric data of an assembly (many parts), the STL file would need many 'solid'/'endsolid' blocks -- which is not allowed by the STL format. Some CAD vendors, notably SpaceClaim, threw the STL standard to the wind by generating ASCII STL files with many 'solid'/'endsolid' blocks, one for each solid part in an assembly. You may think this is a good change, but I find it careless. Most STL file readers use 'endsolid' as the end-of-file marker and stop reading the file. Upon importing a multi-solid STL file into another CAD system, the resulting drawing shows the first solid only; the remainder are ignored. When SpaceClaim users upload STL files to service bureaus for online quotes, they most likely will get a quote for the first part in the assembly tree. Users will leap with joy at the rock-bottom pricing, go ahead and place an order for their assembly, only to scream and yell at the service bureau when only a single part arrives -- instead of the entire assembly. (And then serve themselves as breakfast to their bosses the next day.) Translators could solve this problem by reading beyond the first 'endsolid' keyword to check if there are more solids in the file.
The Invalid Geometry Problem Let me share a little secret with you, one that explains how flipped triangles, missing triangles, and shared facets occur in STL files. You might believe that CAD vendors go through the pain of creating good algorithms to output superior STL files for high end rapid prototyping. Not at all. Their software generates STL files by outputting the render mesh. The render mesh is that bunch of colored triangles that approximate smooth-looking NURBS surfaces on your computer's monitor. The mesh looks good on the screen, but is something that's far from being geometrically-accurate. Little wonder that you end up with lousy STL files. Developers of graphics screen algorithms don't care if their meshes aren't water tight or if the edges aren't stitched properly. Their focus is on how to optimize the 3D render mesh for display, not for rapid prototyping. Over the years, any improvement in STL files has been due to improved graphics and surface tessellation algorithms, a side-effect of advances in the film and animation industry. I find it funny that the RealView graphics in SolidWorks is helping the RP community.
The RPX Format My firms's new RPX format [Rapid Prototyping eXtended] is intended to solve STL's single-part problem. RPX will be similar to the RP format currently offered by the OpenRP Initiative, but will store data of more than one solid -- just as everyone in the RP industry wants. Moreover, the format is structured in a such a way that only valid geometry can be stored in it. RPX stores information related to process, material, finish, layer thickness, color, and so on. It also holds custom data created by end users, such as purchase orders in PDF format for service bureaus who build the parts. When end users send service bureaus RPX files, bureaus will know exactly how to build the parts.
OpenRP Applied: Print3D To prove that RPX works, I co-launched Print3D with Ron Barranco of ZCastings.com as a provider of rapid prototyping services. Free Print3D plug-ins (and stand-alone software) obtains quotes and orders parts directly from within CAD applications. The cost of producing a rapid prototype of your 3D model is generated by the plug-in offline. It prices parts, assemblies, and bulk discounts. Plug-ins are available for Alibre Design, AutoCAD, Inventor, Rhinoceros, SolidWorks, Solid Edge and SpaceClaim; others are under development. This proof-of-concept avoids STL files. When the time comes to place the order, the Print3D plug-in copies your solid models to RP files, and then transmits them to the Print3D production facilities through a secure FTP connection. Delivery is usually the next day. Over the next few weeks Print3D will gain basic and advanced mesh editing, such as hollowing meshes, filling holes, sealing cracks, and stitching faces.
[Deelip Menezes launched the OpenRP Initiative in 2004 and co-launched Print3D in 2008. His company, SYCODE, specializes in developing CAD plug-ins.]
Links: www.sycode.com Quantm Pty of Australia releases v6.0 of its Quantm 3D road and rail alignment visualization software. www.quantm.net Bricsys of Belgium is letting people use its Web-based Vondle project management system free for 30 days at http://www.bricsys.com/en_INTL/vondle/trial.jsp . To help you get started, they have video tutorials at http://www.bricsys.com/en_INTL/vondle/movies.jsp JETCAM International of Monoco ships JETCAM MRP [material requirements planning] as stand-alone software or integrated software package, available for purchase or rental. It includes:
CADsmart of England releases v6 of its CAD skills assessment software with live video recording of candidate assessments. The hour-long Premier assessment figures out where employees need more training, while the quarter-hour Xpress exercise is meant for interviews. http://www.cadsmart.net - - - These news items were posted during the last week at the WorldCAD Access blog < worldcadaccess.typepad.com>:
Seminars & Conferences 4th Annual IntelliCAD World Meeting is October 29-31 in Athens, Greece. (I'll be attending this event.) www.intellicad.org/WorldMeeting2008
Hardware News Colortrac's new SmartLF Ci 40 large-format document scanner costs $6,725; or, as the company puts it, "Provides a new lower price point for cost conscious AEC and CAD users in the post credit-crunch world." www.colortrac.com 3Dconnexion's 3D mice are now supported by Siemens Solid Edge in parts, sheetmetal, weldments, assemblies, and draft documents. www.3Dconnexion.com
Market News Privately-held Catalog Data Solutions reports that its Q3 2008 revenues increased by 95% over a year earlier.
WorthWhile Web http://arstechnica.com/articles/culture/dodgy-digits-behind-the-war-on-piracy.ars
http://blogs.mysql.com/kaj/2008/10/08/on-loyalty-competition-and-underdogs/
http://www.alleyinsider.com/2008/12/startup-advice-how-to-make-the-collapse-work-for-you
Letters to the Editor Re: Interview: SpaceClaim's New CEO "I firmly believe CAD needs a very hard sell. SolidWorks' and PTC's success show you have to hit hard to be successful. Better technology isn't enough and doesn't win the majority of market share. I'd like to know how [the new SpaceClaim ceo] plans to do what others before him haven't been able to do: sell product. "I listed suggestions of what I would do on my blog. It's not pretty but I feel it's the only method that will work: http://tinyurl.com/3r486p "In my opinion SpaceClaim will go broke trying to get Autocad Lite users to convert to SpaceClaim."
Spin Doctor of the Moment "London Bank Bonuses Could Plunge This Year"
Notable Quotable "There’s no doubt that the biggest change [over the last five years] is that most smart people now realize that the world has changed. When I started, I was working in a status quo static world, where the future was expected to be just like the past, but a little sleeker. Now, chaos is the new normal. That makes it easier to sell an idea but a lot harder to sound like a crackpot."
Thank You to Our Subscribers & Donators These great people support upFront.eZine through their contributions of $25 (or more). Thank you, guys!
Copyright 2008 by upFront.eZine Publishing, Ltd. All rights reserved worldwide Article reprint fee US$250.0 and up.
All
trademarks belong to their respective holders.
"upFront.eZine," "Talking About CAD," and
"the business of CADg" are trademarks of
upFront.eZinePublishing, Ltd. |
|
|
|
|
|
|
|