Category — Mechanical

Update 9/9/09: VX Innovator is now $295 (Americas, India, Africa) until September 30, 2009.  Check here for my latest MCAD news.

Since I’ve been posting a lot about affordable Mechanical CAD software, here’s an update on two great deals:

• Alibre’s $99 offer for Design Standard V11.2 ends on September 29, 2009; also on sale for $99 are Alibre Translate and Alibre Training Bundle.  The maintenance contract is still $299, and includes the upgrade to V12 (due on 9/29/09).
• Time to give some attention to VX Innovator: it’s on sale for $195 until September 4, 2009 for Americas, India, and Africa (with a note that price will increase to $295 — we’ll see if that’s a permanent price cut).

I’ ve been playing with Innovator for the past couple days, and will probably buy it, too.  Some initial comments:

• I’ve had problems installing it on two XP systems, but did get it to install on a Vista (yuck!) system.
• There’s not much about it on the web.  I’ve tried searching for VX topics, and had a hard time coming up with useful results;  there’s much more information available on Alibre and CoCreate.
• I was able to get it do some basic stuff without reading the manual, but with a fair amount of fiddling; overall, I’d say it’s not too difficult to use.
• It can do some things Alibre can’t do, and works in a very different manner (which is good — if it was very similar to Alibre, Solidworks, Solid Edge, etc I wouldn’t be interested).

BTW, I’m not interested in running cracked copies of software (e.g. Solidworks).  I’m interested in using software that’s affordable for anyone to use commercially, and I think that companies that produce good software should be rewarded.

I’ve blogged recently about Alibre’s crippling of Design Xpress.  Well, for a limited time, Alibre is now offering Alibre Design Standard for $99; I like this deal and have already paid for a license.

I am using MCAD software to model the PCBs I design because I can catch several types of design errors, including incorrect footprints and mechanical interference.

My requirements are pretty simple; what I want is an affordable system that can:

• import STEP and IGES files, since I want to use the manufacturer’s models if at all possible
• import and extrude DXF files, so I can easily create a model of the printed circuit board itself
• create assemblies using a fair number of parts (>50 should  be enough most of the time)
• export to STEP file (required) and 3D PDF, so I can share my work with others who aren’t using the same CAD software
• be fairly easy to learn and use — I’m primarily a software guy, occasionally designing PCBs, but I’m definitely not a mechanical designer.
• cost under $250

None of currently available free commercial MCAD programs meets all these requirements.  For example, I am fond of CoCreate PE, but it does not export to STEP or 3D PDF, and is limited to 60 parts per assembly.

At $99, however, Alibre Design Standard meets all these requirements, so I will be using it now for all my PCB modeling.  I still want to experiment with and blog about other possibilities, but I don’t expect to get around to that anytime soon.

Some commentators feel this is a desperation move by Alibre.  I think it is a good deal, because:

1. Alibre is getting a lot of publicity
2. They are getting cash flow from Design Xpress users they wouldn’t have gotten otherwise (I’ll call these people, including myself, the non-serious users).  In my case, Design Standard currently isn’t worth $999 (or even $500) to me, so Alibre received $99 from me that they wouldn’t have earned otherwise.
3. Since Alibre has not cut their other pricing, and support and maintenance is not included (Design Standard + 1 year support and upgrades is $398), their support costs are not going to skyrocket, and they probably won’t be devaluing their products.
4. They will still be getting more money from the “serious users” (who would be willing to pay >$500) because these users will be paying annual maintenance.
5. They have increased their chances of upselling in the future.  Once I am used to modelling with Design Standard, I am more likely to pay for maintenance or upgrades in the future.

Go here for my latest MCAD news posts.

Alibre continues to restrict Alibre Design Xpress’ functionality; in Xpress 11 after the 30 day evaluation runs out, you can only import AutoCAD (DWG, DXF) files, and export STL files.

I’ve used Xpress occasionally since it was introduced in 2005, and I’ve never had problems importing STEP  (or IGES) files until recently.  Since I mainly use mechanical CAD to model PCBs populated with manufacturer provided part models (typically in STEP or IGES formats), this means Xpress is no longer useful.  As far as I’m concerned, Xpress is now basically just a trial version — great if you want to evaluate Alibre Design before buying, but not useful on its own.

Since I’m not making any money from the PCBs, my budget for MCAD software is basically $0 (OK, I might go up to $250 for software that did a really great job).  If I were primarily doing mechanical design, especially for money, then my budget would be different.

I’m still thinking about what I want to do; my default option is to model in CoCreate PE, which only exports STL and VRML files, but at least it imports DWG, DXF, STP, and IGES files, so it’s still easy to model PCBs in CoCreate and check that all the pieces fit together.

Go here for my latest MCAD news posts.

It appears that Alibre is now trying to keep Design Xpress (the free version, with limitations such as five unique parts per assembly) a secret.  There are now no references to Design Xpress on Alibre’s home page or Products page.  Many of the links, such as the product page for Design Xpress and the feature comparision, now return “Page does not exist” errors.  However, a page giving the differences between Design Xpress and the Design trial still exists.

Although I haven’t tried downloading and installing to verify, it appears Xpress still does exist, since the registration page for the Design Professional trial still says: “After 30 days your trial converts to Alibre Design Xpress, which has no time limit.”

Go here for my latest MCAD news posts.

CAD Exchanger is a new program written by Roman Lygin designed to ease CAD model interchange by providing file viewing and translation for a variety of 3-D CAD formats.

The beta currently supports importing, viewing, and exporting IGES, STEP, STL, and Open CASCADE BRep files; in the future, more formats will be supported.  It is based on Open CASCADE; it is currently free but not open source.

CAD Exchanger does not currently support measuring.  I prefer that the CAD Exchanger team concentrate on adding and improving its file translation abilities; there are already fine free solutions for measuring STEP files.

I tried CAD Exchanger using the same Norcomp HD26M model I used with other CAD programs.  The user interface does not currently support drag-and-drop.  The HD26M model loaded in a reasonable time; 3D performance (rotate, zoom, pan) is good, even on a laptop with crappy Intel graphics.  CAD Exchanger provides a nice selection of pre-defined views.  I didn’t try exporting.

Here is a picture of CAD Exchanger in action:

HD26M model in CAD Exchanger

Why am I interested in viewing and measuring STEP files?  Because I can make a better automation PCB if I can use STEP files.  Mechanical engineers, of course, like 3D models they can import and use in assemblies, but I am mainly concerned with PCBs.

There are a variety of standard 3D file formats, including IGES, STEP, 3D PDF, STL, VRML, ACIS, and 3D PDFs.  The most common formats for electrical components are IGES, STEP, and, recently, 3D PDFs.  My experience is that STEP files typically import with fewer problems than IGES; 3D PDFs are very nice for viewing parts, but unless the file creator took the proper steps, cannot be used for measuring.

My uses for STEP files include:

• Viewing parts.  I can’t synthesize 3D parts in my head from a set of 2D drawings, and sometimes it’s very useful to see what a part looks like.   I really like to have real parts to play with, but that’s not always possible.
• Sometimes the manufacturer’s 2D prints do not give all the information I want to create my PCB component shape.  I can get any dimension I want from a STEP file.
• It’s very easy to screw up PCB connectors.  Doing a quick assembly of the PCB and components lets me verify that my drill sizes are correct, check for cable orientation, and such.

Since I am not doing any heavy duty mechanical design work, I did a bit of research into free MCAD programs that can view and measure STEP files, and preferably create small assemblies.  I found one program specifically designed as a STEP file viewer, IDA-STEP.   The free version of IDA-STEP does not measure.

However, most free MCAD programs can import and then measure STEP files.  I took a quick look at five different programs, listed below.  CoCreate PE is my favorite of the bunch; it seems the best match for a non-mechanical guy like me.

1. CoCreate PE
2. PowerSHAPE-e
3. Alibre Design Xpress Note: since Alibre has dropped STEP import from Design Xpress, it is no longer a good choice.
4. IDA-STEP
5. Acrobat 3D PDF
6. CAD Exchanger (a program to convert between CAD file formats, but it also works as a viewer)
7. CADFaster|QuickStep is another CAD file viewer with free and paid versions; when I get time, I will give it a short test.

Note that the free versions of MCAD programs exist primarily for marketing reasons, and the terms can (and have) changed at any time.

There are other free Mechanical CAD programs that might be able to read STEP files, including:

• Medusa4 Personal, which runs on Linux and Windows, but can’t export data and all drawings are marked.
• Kompas-3D Light, which cannot create assemblies.
• Autodesk Inventor LT, which cannot create assemblies.

CoCreate Personal Edition is the free version of the CoCreate CAD program.  CoCreate PE requires an Internet connection every 3 days, can import IGES, STEP, DWG, and DXF files, export STL and VRML files, and is limited to a maximum of 60 unique parts per assembly.

You can drag and drop STEP files onto CoCreate.  It has a pretty complete set of pre-defined views.  Performance on my system is snappy.  I found measuring easy.  Hmm, so far pretty short and sweet – that’s because I like it.  It’s my favorite of the four programs I’ve tried (CoCreate, Alibre, PowerSHAPE, IDA STEP) – it seems the most intuitive to me, and was definitely the easiest to use to measure parts.

Note that like all other free CAD programs, the terms may change in the future.  For example, PTC (the current owner of CoCreate) had a free CAD program called Pro/Desktop that was later dropped (IIRC, the current users were given a five year license).

Measuring HD26M with CoCreate

PowerSHAPE-e is the free version of Delcam’s PowerSHAPE CAD program.  It has all of the functionality of the PowerSHAPE program, except that you can only save files using the encrypted PowerSHAPE-e file format, which cannot be read by any other CAD software (including PowerSHAPE).  You can use the Delcam Exchange program to save in another file format; I believe the cost is £200 (~$300) per file.

The Exchange software provides CAD file translation for a very large number of CAD file formats.  Importing the files is free, but exporting to another format costs money (currently £34 (~$50) per file for non-PowerSHAPE-e files).  The Exchange software can be run stand-alone, or from within PowerSHAPE-e.

You can set a variety of import options when directly importing STEP files using Exchange; there are no options when importing using PowerSHAPE-e.  However, you cannot measure parts in Exchange.

You can drag and drop STEP files onto PowerSHAPE-e.  One nice feature are all the pre-defined views – just click on the icon to spin the part into that orientation.  However, I had to look up how to manually rotate a part: you have to hold down the middle mouse button.  Part manipulation speed is good.

You use the calculator to measure.  When measuring, PowerSHAPE-e seemed a bit behind where I wanted it to be; it might need a faster system than my Athlon 2800 + older Quadro card

Viewing HD26M connector with PowerSHAPE-e

Update 6/24/09: Alibre wants to keep Design Xpress secret, and has removed several of the pages linked to below

Update 8/7/09: Alibre has removed STEP file import from Design Xpress, so it’s no longer useful as a STEP file viewer.  (OK, you can import STEP files during the first 30 days, but after that, you’ll have to pay or find something else).  Go here for or my latest MCAD news posts.

Alibre Design Xpress is the free version of Alibre Design.  It is significantly less capable than Alibre Design Standard.  Limitation include only 5 unique parts per assembly, no advanced modeling tools, and no advanced drawing functions.  Alibre has a feature comparision here.  However, Xpress can still do a lot, including create assemblies (many free versions can’t), import and export files in various formats [import DXF, DWG; export STL], be used professionally, and create 3D PDFs.

With the free version of any proprietary software, the terms can change at any time.  My Design Xpress license allows 25 5 [changed when updated to V11] unique parts per assembly.  Until recently, the normal Xpress limit was 10 unique parts; now it is 5.

In any case, Design Xpress makes a fine STEP file viewer [for 30 days].   You can drag and drop STEP files onto the Xpress Control Panel (but not a part or assembly window), or use the Import menu or button.  This brings up the Import dialog box, which controls how the STEP file is imported.

Alibre 11 STEP file import options

STEP files don’t always import correctly, so it’s good to have these options available.  Note that these options do affect how quickly the part is imported.

I tested Alibre using the same Norcomp HD26M part; it imported without a problem.   I rotated, panned, and zoomed the part without problems.  Since I often end up with the part at weird angles, I appreciate the View–>Orient–>To Plane… menu which snaps the part view back to a plane.

I found measuring a little tricky at first, mostly because what I thought I was selecting wasn’t what I really was.  I was viewing the part looking straight at the front; when I rotated the part a bit (as shown in the picture below), I easily selected the features I wanted.

The Linear/Pairs measurement options takes the first mouse clicks after you select it; I could not figure out how to reset the points being measured without closing and re-opening the measure dialog.  So I had to be careful where I clicked the first two times.

HD26M STEP model in Alibre Design Express

The German company LKSoft makes a a free STEP file viewer; the current version is IDA-STEP V4.  The free version does not allow measuring; measuring, printing, editing, importing, and exporting are extra cost add-on modules.

IDA-STEP is an unusual STEP viewer, because it is written in Java (possibly using the Eclipse RCP), and because it is oriented towards PCB design – just take a look at the available components at the LKSoft store.

I spent a little time playing around with it using the STEP model of the Norcomp 180-026-103 HD26M connector.  It seemed to work well; rotating the model was fast.  I wish I could drag & drop STEP models onto IDA-STEP.   As noted, the free version is restricted to viewing; it does not allow measuring.

HD26M in IDA-STEP