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Vellum/Concepts Unlimited to VW Mechanical?

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I'm exploring other CAD packages that run on the MAC and thinking on switching from Concepts Unlimited to VW Mechanical for my 3D CAD. I mainly do mechanical mechanisms and the like. Has any one else had any experience with this change and let me know what I'd be in for. The assembly and mechanical features of CU is very limited and it's a struggle to manage a multiple part model. Does VW handle assemblies well? How is this done in VW? Is it similar to other CAD packages like SW or SE?

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No, it is not similar to SW, SE, Inventor, or Alibre. It doesn't handle assemblies particularly well. It's 3d functionality and constraint system are seriously limited when compared to other MCAD packages.

What VW Mechanical does really well is 2d drawing. It has boatloads of parametric symbols that can speed up 2d drawing time.

As I began modeling more of my machines in 3d I was becoming frustrated with VW because the 3d snapping is limited, and 3d constraints don't exist. (i.e. you can't constrain a 3d gear to a 3d shaft, in fact just trying to line them up in 3d requires several workaround steps) I decided to add another software package and purchased Alibre Design. After demoing all of the big mid-range packages (SW, SE, & Inventor) I found that Alibre had all of the functionality I needed at about 20% of the price. I have been REALLY happy using the software. I've designed several new machines and sheet metal enclosures over the last couple of months and the process has been great. Working in a truly 3d parametric environment has saved me tons of time (especially when revising designs).

Here are the features that are particularly useful in other MCAD packages and absent from VW Mechanical:

-3d constraints

-Geometry that can be derived from other parts and automatically update. (i.e. a shaft should stick out .250" from the end of two bearings, regardless how far apart the bearings are)

-Exploded views that are derived from an assembly, and dynamically linked

-Mechanical simulation of linkages


-Part history tree where features can be removed/re-ordered

-Dynamically generated 2d drawings that are linked to the 3d model (VW's viewports do achieve this partially)

-Sheet metal parts that can be unfolded into a flat pattern, automatically accounting for bend allowances

-Smart features like bolt circles that can be updated either manually or derived from mating parts

-Threaded 3d holes, and 3d holes whose callouts are automatically generated in a 2d drawing

-Fast, interactive shaded 3d views with clear visual cues. This is one that sounds silly, but I was stunned to see how productive it was to constantly work on a well-shaded model that updates as fast as I can spin my mouse. Also, having the software detect edges or faces and highlight them in a bright color is much more responsive than the eight square selection handles that VW uses. Again, sounds petty but it really helps speed up modeling time.

Those are the missing features that spring to mind, I'm sure there's more...

I still use VW when I have to bang out a 2d drawing that doesn't require 3d, because it's 2d tools are really elegant. However, I would imagine that Vellum is probably an excellent drawing program as well. If you are looking for a good 3D mechanical CAD package, I honestly can't recommend VWM when compared to SW, SE, Inventor, or Alibre.

Of course the MCAD package I mentioned are all PC-only, which is a drag. I ended up building a very fast Athlon64 PC for about $500 that runs Alibre very well. In the end, for me, it was still a better solution than using VW Mechanical for 3d work.

I believe you can demo Vectorworks (without Mech). Mechanical mostly just adds a lot of parametric symbols and a BOM feature, but the 3d snapping and 2d constraints are the same. This should give you a clear picture of whether VW would bring you much advantage over your current software.

Hope that helps, best of luck.

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Thanks for the info. That's what I thought it was but needed to hear it from a user. Concepts Unlimited has a great interface and one can model very fast. What it lacks are good 2D drawing tools and it's ability to manage projects with many parts. I'm currenlty on their case to fix these and other issues upon which it will be an awsome 3D CAD modeling package. Other things I'm trying to get added to CU is the ability for a designer to add value to the model during creation of parts. For example, when a shaft is created to fit a bearing, the tolerance of the shaft is determined and this tolerance should be entered into the model at that point in time. Trying to remember this when making a print days or weeks later does not work well. How do you manage projects in your CAD package?

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In regards to tolerancing, yes Alibre does allow you specify tolerance during model construction (or you can add during the drawing phase as well). As you say, this is more convenient than trying to remember all of the design criteria as you are laying out 2d drawings days/weeks later.

Alibre, like SW, views everything in the part/assembly paradigm. Every distinct object is a part with a name, part #, and other fabrication information. Two or more parts can be aligned and constrained in an assembly, and sub-assemblies can be aligned and constrained in another assembly. This makes project management very fluid and concise. Because the software requires you to build individual parts, a BOM can be created instantly for any assembly.

All geometry is parametric and can be edited at any time. For example, I designed an electrical enclosure for the motion controllers that we build. The enclosure is a two-part sheet metal enclosure with a bunch of cut-outs & PEM fasteners for mounting the internal components. After constructing the prototype, I felt that the enclosures should be a little bigger to allow for easier wiring during assembly. To make the change, all I had to do is edit one dimension in the geometry history for the base of the enclosure. Based on that change all the cover of the case automatically adjusted, and all of the components shifted as needed updating hole placements, etc. All of the 2d shop drawings were automatically updated, making the whole process take about 10 minutes. Similar experience when adjusting some of our electric winch designs, very smooth.

I should note that though you build distinct parts, the parts can be inter-related. For instance, a mounting plate can derive its hole pattern from the mating pillow block, etc. I found that even though the work flow was different from Vectorworks, I was able to be productive in a couple of days.

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If you have any further interest in Alibre, you can check out their forum:


If you are looking for just a 2d package to augment CU, VW Mech may be a good option. But for a parameteric 3d MCAD application, probably best to look elsewhere.

FWIW, I have been using VW since it was MiniCAD 5 and still use it for 2d-only work.

I felt compelled to say something nice about VW on their board [smile]

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Wow, after taking a good look at Alibre, it looks very "Industry standard" with it's interface and assembly manager. Even a bit easier to learn. Too bad I'm fond of MAC. I did call Alibre and they do have several users using Virtual PC and running it on a MAC but I have never liked running under VPC. They have been getting more requests to support MAC OS X and I was sure to put in my vote. They said if they get enough they would do it.

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Yeah, it's really great. I was looking into financing a purchase of SW before stumbling into Alibre. It performs as advertised at about 20% of the cost of SW & Inventor.

The support is quite good as well. My first weekend of using the software I had an issue and posted a question to their user forum. I got a phone call 1 hour later from one of the engineer's who saw my post. He called from home, on a Saturday. I was stunned!

Alibre, like other MCAD packages, does require quite a bit of computer muscle to run well (fast processor, 1 Gig of RAM, fast video card, etc.) so I wouldn't run it with VPC. Like you, I really enjoy my Mac, and now it runs quite nicely right next to my Athlon PC [smile] For me, it was worth $500 of computer to be able to run the software.

Best of luck!

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  • 8 months later...

Speaking as an Ashlar-Vellum user (best not to go there with regards to Concepts :-)) I can relate to what you describe. Here we use Ashlar-Vellum Cobalt (pretty much the same as CU) with Ashlar's Graphite for drafting, and VectorWorks Industry Series and VX Designer.

I have trialed Alibre but as product designers it doesn't handle surfaces well enough for us (hence the reason we also use VX). What you can do is get the free Alibre Design Xpress to try it out. For machine design I would choose Alibre every time over the mid range big boys.

As a CU user though there is one BIG advantage in going Alibre in that both CU and Alibre use the ACIS modelling kernel, so 3D models from CU will sail into Alibre perfectly, and vice versa (same also applies to Ashlar as well).

So what you can do is create all the tricky stuff in CU and import as a component into Alibre for assembly and drafting and BOM.

As for the Mac vs PC thing, wait until next year and you can buy a new G5 with an Intel processor inside and run Windows and OSX natively on the same machine!

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