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Free 2D Mechanical CAD Software

I now have a Trac page to keep track of the interesting 2D mechanical CAD software I have come across.

There are at least three impressive and free AutoCAD clones available; I’ve tried all three a bit, mainly for viewing DWG files, playing with PCB outlines, and modifying electrical schematics (for creating electrical schematics, I highly recommend using a dedicated program, unless most of your schematics have moved into PCB schematics).

Unlike in the 3d MCAD world, I believe there are some impressive open source 2D MCAD programs, but I haven’t found time to research them…yet.

July 14, 2014   No Comments

Affordable 3D Mechanical CAD Directory

I’ve just created a Trac page with my directory of free, affordable, and semi-affordable 3D MCAD programs.

I’ve been wanting to create some directories for a while, so I can have a central place for information, instead of having it spread out among various blog posts.  In the past, I’ve used WordPress pages (for Piezo Motors and Industrial Robot Resources), but I’ve decided I like using Trac better, so I will be creating my new directories on my Trac site.

As I come across new or updated information, I will update these directories.  I use them myself, and I hope they are useful to others, too.

July 2, 2014   No Comments

3D Models of Automation PCBs

I’ve been investigating affordable, automatic creation of 3D PCBs models; what I’ve found doesn’t match up well with my needs.

I would like an easier way to create accurate models of automation PCBs, such as break out boards, which mainly use through-hole connectors (think of something like my FP-SMC-1 PCB).  I want to use the model to verify my footprints, check that everything fits together mechanically (for example, fits into the DIN rail holder without any conflicts), and do an initial check that the board will be easy to use (enough space between connectors, etc).

I’m not interested in an approximate visualization; I want accurate an accurate model (preferably exportable in STEP format) created from manufacturer’s STEP or IGES models (which are typically available for connectors).

I took a quick glance at PCB Pool’s 3D visualization service, DesignSpark PCB, and KiCAD, and felt the reward wasn’t worth the effort of trying to get everything set up.  Later I plan on looking into this again, but for right now, I’m back to using Alibre Geomagic Design and having fun trying to get everything to mate.  (As far as I can tell, DesignSpark Mechanical does not support mating, and it doesn’t export STEP files, so GD is a better path for me).

May 31, 2014   No Comments

Notes On Creating The End Effector

I created my end effector mostly using “Spaceclaim Light”, officially known as DesignSpark Mechanical (DSM).  Since my goal was to create something I could use as quickly as possible, I have not spent the time to become an expert user.

The DesignSpark Mechanical Background

Electrocomponents (parent company of RS Components and Allied Electronics) offers a variety of free tools and other design resources (such as forums) on their DesignSpark website.   The most impressive tools are:

  • DesignSpark PCB, based on Easy-PC from Number One Systems
  • DesignSpark Mechanical, a carefully cut-down version of SpaceClaim.  DSM is a very powerful program, but lacks key features (such as useful import and export formats; assembly constraints also appear to be missing) needed to replace SpaceClaim, SolidWorks, SolidEdge, and such for hard-core mechanical design.  On the other hand, with features such as IDF import, DSM appears to be a good match for creating 3D PCB designs.

Electrocomponents is betting their costs will be more than covered by increased component sales and much better awareness (in other words, I’d say the cost of is a much better use of marketing money than direct advertisements).

Creating Parts

Creating parts in DSM reminds me of creating parts in SketchUp, except that SketchUp is really oriented towards architecture, while it’s clear DSM is meant for mechanical design.  I like being able to easily input exact dimensions.  It’s neat being able to push and pull 3D parts.

I didn’t have much difficulty creating my simple parts.  The hardest was figuring out how to create the cones for the vacuum grippers (I created a triangular sketch, then revolved it 360 degrees around the center axis – it did take a few experiments to figure out the exact sequence of mouse clicks).

I’m still not a fan of the Microsoft ribbon interface.  I don’t care for it in MS Office, and I don’t like it any better in DSM.

Assembling Parts

Well, my parts aren’t really assembled.  I got so frustrated trying to assemble them I was tempted to go back to Alibre Design (now Geomagic Design), but since this isn’t a real design, I just moved them by eye until I was happy with the layout.

At least you can move components (groups of parts) by selecting the top level component; if you’re not careful, you’ll end up moving just a part of the component.

Since DSM is so new, there is very little community support, and the documentation is pretty skimpy.  All I could find on making assemblies is this brief tutorial (see Section 3; I’m pretty sure all that’s happening is the part is moved, with no constraints) and in the FAQ (see How Do I Make Assembly Models?).

What I want to do is set assembly constraints such as making planes parallel, aligning axes, and such.  From my searching, it appears SpaceClaim has an assembly constraints toolbar; I couldn’t find anything similar in DSM.

Getting The Result Into WinCAPS III

I will be using my model in the Denso WinCAPS III robot simulator, which can only import DirectX and VRML files.  As is typical of most MCAD software, DSM does not export to VRML.  However, it does export to STL, and fortunately there are a number of STL to VRML converters.

I used meshconv to convert to VRML; its documentation isn’t great, but it’s not too hard to use.  For example, to convert fixture.stl to fixture.wxl I used this command line:

meshconv.exe fixture.stl -c wrl -o fixture -vrmlver 2


Based on my small project, I’d say that if you’re hoping for a free replacement for the professional MCAD programs, you’ll be disappointed in DesignSpark Mechanical.  But if you’re looking for a SketchUp-style program oriented towards mechanical, especially electro-mechanical, design then check it out.

I may have to tweak my model bit for different simulation situations; I think that will be pretty easy to do.

Sometime I need write an update about the low cost MCAD market, since there have been a lot of changes, including the introduction of DSM, and Autodesk buying Delcam (which may lead to changes with the free PowerShape-e MCAD software).

February 4, 2014   No Comments

Autodesk 123D MCAD and PCB Models

Autodesk just released the beta version of the 123D 3D mechanical CAD program.  It’s meant for hobbyists, but Autodesk surprised me by including both STEP file import and export.  (Free or low cost commercial CAD programs almost always don’t include free STEP file export).

123D is the standalone version of Inventor Fusion, so it is a direct modeler (not a history based like SolidWorks or Alibre).  So put together free, easier to use (direct modeling), and STEP file import/export, and it should work great for creating 3D PCB models.  There could be some problems, such as assembly limitations (such as a low maximum number of parts), or the EULA (so far the 123D End User License Agreement appears to be the standard Autodesk one, with no mentions of restrictions on commercial use).

I haven’t been able to check out 123D’s PCB prowess yet because I haven’t been able to get it to start successfully.  I’ll give it another try in a while.

May 22, 2011   No Comments

Affordable 3D MCAD

These are low cost programs suitable for designing mechanical assemblies.

Don’t forget you can use multiple programs to overcome the limitations of one program.

Open Source

Both NaroCAD and FreeCAD are under active development, but I’m pretty sure neither one is anywhere close to ready for production use.

They are still worth checking out, because they might have enough functionality for what you need to do.

Free Commercial MCAD

These programs typically have a lot of limitations, the terms can change at any time, but they are still potentially useful.

  1. PowerSHAPE-e.  Very powerful, but costs money to export.
  2. Autodesk 123D.  Appears to be good match for modeling personal PCBs; has STEP import and export.
  3. CoCreate PE, now creo elements/direct PE.  Limited import and export, limited to 60 parts, but good to see PTC has moved it into the Creo world.
  4. MEDUSA4 Personal.  Available for Windows and Linux.
  5. Autodesk Labs Inventor Fusion Preview.  Time limited preview of the Fusion direct editing MCAD software.

MCAD Under $500

  1. Alibre PE ($199).  Very limited import and export options.

MCAD Under $1500

  1. IronCAD Draft ($595).  Not a full MCAD program (e.g. can’t create parts), but can create assemblies.
  2. Alibre Professional ($699).  Adds import/export options and more.
  3. VariCAD ($710).  Available for Windows and Linux.
  4. IronCAD INNOVATE XG (~$1300).  Meant for conceptual design, but according to the product comparison it includes “assembly modeling within  a single scene”.
  5. Alibre Expert ($1399).  Adds CAM, Motion, MoI, and more.
  6. The combination of Rhino ($995 list, available for less) and RhinoWorks ($595, adds parametric and assembly capabilities) might work well.

Other Options worth considering

  1. ZW3D ($2500 for Standard).  ZW3D 2011 adds direct editing.
  2. IRONCAD ($4000 and up).  Innovative MCAD.
  3. SpaceClaim ($2450 and up).  Well known for easy direct editing.

Update 4/18/2011: Added Rhino/RhinoWorks

Update 5/22/2011: Added Autodesk 123D, updated Alibre PE price.

April 1, 2011   No Comments

A More Detailed Look At Delcam PowerShape-e

Yep, this is from a while back, but I think it’s worth pointing out Deelip Menezes’ 7-part series on Delcam PowerShape 2010.

I did play around a bit with PowerShape-e 2009, but I found it hard to figure out.  OK, I didn’t do any tutorials, but I’ve had better luck figuring out other MCAD programs.  Since I now have licenses for Alibre Design and VX/ZW3D and my time is limited, I haven’t used free but limited programs like PowerShape-e or CoCreate-PE in over a year.

The PowerShape-e business model (not feature limited compared to PowerShape, but you pay every time you want to get your data out) doesn’t match well with my requirements (that’s the same reason I don’t like using “free” PCB design software that is locked to a specific proto house).

If you’re looking at acquiring MCAD software, I recommend considering all the CAD design software possibilities, including lesser known programs such as PowerShape, IRONCAD, KeyCreator, SpaceClaim, ZW3D, and Solid Edge.  And I highly recommend reading Deelip’s blog; he is a blogging machine (1000 posts in about 4.5 years), and has written many interesting multi-part series.

November 16, 2010   No Comments

Mechanical CAD, Special Deals, and Me

When I look at my traffic stats, I see there’s a lot of interest in affordable mechanical CAD.  I think that interest is good: I do not believe in pirating software, and I believe there is a place for affordable MCAD (and affordable CAM for desktop CNC machines), especially for personal use and as a tool for people who aren’t primarily mechanical designers.

I own licenses of Alibre Design Standard V11 (which I bought during the $99 sale) and VX Innovator V14 (which I bought on sale for $195).  I also have free licenses for DoubleCAD XT and CoCreate PE.

I mainly plan on using Alibre and VX Innovator, and reporting my experiences here.  They are somewhat complimentary; Alibre is a pretty standard history-based parametric modeler (with some nice features such as Acrobat 3D output), and VX is a hybrid modeler (solid and surface).

DoubleCAD looks very capable for 2D CAD, but I don’t expect to use it a lot.  I mainly use it for viewing and experimenting with DXF files created by Eagle PCB.

I do like CoCreate PE, but don’t plan on using it much now that I have Alibre Design and VX Innovator.  It’s limited to 60 parts per assembly, which I could easily exceed when modeling a PCB, and cannot export STEP files.  PTC has offered some very big discounts in the past to upgrade to the full version, but the annual maintenance  cost is way too high for my budget.

However, this is not a MCAD blog; my interest in still primarily in automation software and system integration (including PCBs).  OK, I do plan on writing more, but mostly I want to write about my experiences with affordable MCAD.  I do not have the time or interest to keep up with all the latest deals.  But I still might mention deals or MCAD news occasionally.

If you want to keep up on the latest special offers, you should visit MCAD sites such as and World CAD Access.  Also, if you register for the free versions (e.g. Alibre Design Xpress, CoCreate PE, DoubleCAD XT) you will receive e-mail offers.

Alibre has had a lot of good deals (maybe too many).  I’m currently sticking with V11 because I haven’t used it enough, and the improvements in V12 aren’t compelling for my uses.

VX had another sale on VX Innovator around Christmas, but they aren’t as good at marketing as Alibre; if you’re interested in a deal on VX, you should check their web store frequently.

Kubotek has had some sales, too, such as Kubotek Spectrum for $99; current deals include $700 off KeyCreator.

My latest MCAD news is here.

January 14, 2010   3 Comments

Verifying PCB Footprints

A great way to waste time and money on Printed Circuit Boards (PCBs) is to create them with the wrong footprints.  It’s worth spending the time to verify before ordering.

The footprint is what a part looks like on the PCB: the holes, the pads, the silkscreen, etc.  PCB design software typically comes with footprint libraries, but some people (including myself and the guys at Sparkfun) prefer to do their own.

It’s easy to make a mistake when creating your own footprints.  You should still check all footprints, because the creator could have made a mistake or it could have been designed for a different part (for example, not all DB9F right angle through hole connectors have the same footprint).

There are two ways of verifying a part’s PCB footprint:

Model the PCB using a MCAD (mechanical CAD) program

  1. You have to create a PCB first that uses the footprint.
  2. You need a 3D model of the part, preferably from the manufacturer.
  3. You need a suitable MCAD program.  Links to some free personal use possibilities (such as CoCreate PE, PowerSHAPE-e, and Medusa4 Personal) are here.
  4. I discussed how I modeled the FP-SMC-1 here.

Mock the PCB using a life size printout

  1. You have to have the parts you are going to verify.  I like to have the parts first, anyway, since I like to see what the look like and how they work before I use them in a design.
  2. You have to create a PCB first that uses the footprint.
  3. You then print the footprint at life size (1:1 scale), with the pads, holes, and (optional) silkscreen showing.  You should check that the printout really is life size (printers aren’t perfect).
  4. Cut out the PCB, and then mount the parts onto the paper.  I find it’s easier to punch through hole parts through the paper when it’s backed by something like foam.
  5. Check the footprint with the parts mounted and removed: holes in right places, pads line up, silkscreen is visible, etc.
Parts inserted into paper PCB printout

Parts inserted into paper PCB printout

Pictured above is a printout of the FP-SMC-1 PCB layout with the parts inserted.  You can see that the text is readable, and silkscreen outlines appear correct, and such.

Paper PCB printout after parts inserted

Paper PCB printout after parts inserted

Pictured above is a view of the FP-SMC-1 layout printout after I removed the parts.  You can see, especially in the larger version, that all the holes (made by the connectors’ pins) line up with the layout’s holes.  (Click on the picture to see the full size version).

In some ways, it’s easier to use the second method.  MCAD programs are fun, but they do have a substantial learning curve; I’ve found mating parts is often very challenging.  But it can also be challenging to poke parts through paper accurately, and I haven’t tried the second method with surface mount parts yet.

November 4, 2009   4 Comments

Expiring MCAD Deals: VX Innovator 9/4, Alibre 9/29

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.

September 2, 2009   No Comments