Merging modern software development with electrons and metal
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Category — Mechanical

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

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

New Cheap But Limited 3D MCAD Choices

If you want to learn MCAD or make models to build in your garage, there are a couple of new choices:

  • Siemens PLM Systems is making the student edition of Solid Edge available to basically anyone for free.  Limitations include no commercial use, files incompatible with commercial Solid Edge, and watermarked drawings.  See Deelip’s post for more details.
  • ASCON has introduced Kompas 3D-Home for $50.  David Levin says that Kompas 3D-Home cannot be used commercially, but otherwise has no limitations.

September 7, 2011   No Comments

The Turbulent MCAD Market

I’m not interested in being a 3D Mechanical CAD (MCAD) journalist, but since has lot happened in the last year, it’s time for my summary.

The “Big 4” have been up to a lot:

  • SolidWorks is being brought closer to its parent (Dassault Systèmes).  It’s highly probably that a new version based on the CATIA V6 CGM kernel is coming, possibly cloud based.
  • PTC has put Pro/E out to pasture, and is busy trying to get its new Creo components out.  Creo is supposedly to be modular (including history based and direct modelling modules) and app-oriented.  The vision sounds nice, but I suspect that the actual operational and pricing details will make it evolutionary, not revolutionary.
  • AutoDesk is adding direct modelling to Inventor via the Fusion program.  The free 123D program is a cut-down, stand-alone version of Inventor fusion.  123D looks quite useful, but I expect it’ll be neutered if it starts to impact Inventor revenues.
  • Siemens PLM Systems is finally getting its Solid Edge act together.  They’re concentrating on making Solid Edge the best program for machine design, and Synchronous Technology V3 (direct and history based modelling) has been getting good reviews.

There’s been even more change with many of the smaller players:

  • 3D Systems recently bought Alibre.  A few months ago Alibre introduced a $1500 bundle consisting of a RapMan 3D printer, Alibre Design Personal, and MoI.  I’ll be interested to see what happens next.
  • The $97 Alibre Design Standard deal really was a great deal, just for the translators and 3D PDF output alone, but the recent pricing and capability changes (e.g. removing almost all import and export options from AD Personal) really neutered the entry level version.
  • I’m hopeful that 3DS will provide resources so Alibre can keep improving (especially since I just paid for Alibre maintenance!)
  • ZWCAD of China bought VX, and renamed it ZW3D.
    • On the positive side, ZWCAD is trying to treat customers well, there have been no US layoffs as far as I know, they have been investing money into ZW3D (licensing more components, adding more developers, etc), appear to be listening, and probably have a good upgrade policy.
    • On the other hand, it’s taking a  (long?) while for them to get up to speed, they’re going to a reseller-only approach (e.g. you have to contact your reseller to upgrade), and they really need to spend some money and hire some good US marketing folks.
    • For example, when ZWCAD took over, they gave all customers a free upgrade to the next level.  So if you had VX Innovate, you got upgraded to ZW3D 2010 Standard, if you had VX standard, you were upgraded to ZW3D 2010 Professional.  I think this was a great gesture, but ZWCAD never received any publicity for this.
  • Think3 users are in a huge mess, and should start looking elsewhere, since there are now two versions, one from Versata, and one from the Italian bankruptcy trustee.  Deelip is the place to go for all the details.
  • I plan on discussing my experiences with Alibre, ZW3D, and 123D, but I won’t make any promises on how often I’ll have time for such posts.

    August 2, 2011   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

    Alibre Design and DXF Blocks

    Many DXF files use blocks.  A blocks defines an object, which then be placed in many locations, and each location can be scaled and rotated individually.   For example, the standard Eagle PCB DXF export ULP uses one block for each different style of pad (circular, square, etc), and then scales, rotates, and places these blocks for each individual pad.

    But blocks aren’t so great when you’re importing them into Alibre Design (AD).  I’ll look at a few issues by trying to extrude the Phoenix ZFK3DS 1,5-5,08 (1704415) terminal block outline; for example, I might want to model a cover for the end block (1704554).  The files are available in a ZIP archive here Alibre and DXF

    The DXF file provided by Phoenix uses blocks for all the views.  I removed the views I didn’t want; the resulting file is Phoenix 1704415 Profile – block.DXF, shown below in DoubleCAD XT.  You can see the blocks on the right.

    Phoenx 1704415 Profile using blocks

    Phoenix 1704415 Profile using blocks

    I can’t extrude that profile; I need to remove the pins and the pegs.  But I can’t edit the block in the drawing (left side of screen).  In the Alibre sketch mode, I can only move it, delete it, or copy it.   In the DoubleCAD drawing I can only scale, rotate, move, copy, or delete the block.

    But I can edit the block in DoubleCAD by selecting the block in the block tab (shown on the right), and pressing the EC (Edit Content) button.  The block is now displayed in the drawing area, and I can edit it, then press the check mark (next to EC) when I am done.  The final result is shown below and in the Phoenix 1704415 Profile – block for Extrude.dxf file.  Note that when you edit a block, all objects based on that block will update when you finish editing.

    Phoenix 1704415 Profile - using blocks, edited

    Phoenix 1704415 Profile - using blocks, edited

    Another approach is to change to a no-block approach by editing the block you want, selecting everything, copying it, closing the block editor, pasting the copied part into the main drawing, and finally deleting all the blocks in the block tab (when you delete a block, all the objects based on that block are deleted).  The result is in the Phoenix 1704415 Profile – No Block.dxf file.

    With the no-block file, you can delete the stuff you don’t want in either DoubleCAD or import it into Alibre Design and delete it in AD’s sketch editor.  The no-block approach isn’t good for a circuit board full of blocks, but it works great for a single profile.

    There are some other differences between the block and no-block approaches in Alibre Design.  Alibre has a non-obvious approach to pasting in sketches: “normal” pasting (Ctrl-V) always pastes the clipboard content in the same position relative to the origin; paste stamping (Ctrl-T) lets you place it where you want (press ESC when you’re done pasting).

    The approach is always the same for getting a DXF file into a sketch: import (which opens an Alibre drawing), open sketch mode, select everything, and then paste it (Ctrl-T or Ctrl-V) into the desired sketch.

    So far I’ve found that blocks don’t paste correctly; they get pasted with some sort of an offset, whether using paste or the paste stamper.  Non-block DXF drawings paste correctly.   But it’s easier to move blocks in Alibre sketches: just select them and drag.  To move a non-block figure, you have to select all of it, cut it (Ctrl-X), paste stamp it (Ctrl-T), move it where you want, and then quit stamping (Esc).

    Here’s a picture of the finished profile extruded in Alibre:

    Extruded DXF profile

    Extruded DXF profile

    I’ve used DoubleCAD XT for all my DXF manipulations because it’s free and it works for me.  You should be able to do the same things with any other high quality AutoCAD clone.  DraftSight is another free AutoCAD clone worth checking out; it’s available on Windows, Mac, and (real soon now) Linux.

    October 20, 2010   No Comments

    Machine Design on DIY Manufacturing

    Machine Design has an article on Do It Yourself Manufacturing, basically talking about small (often 1 person) niche companies doing design with CoCreate PE or Alibre Design and manufacturing using personal CNC tools from Tormach.

    September 3, 2010   No Comments