Alibre v. Solidworks . . . redux

[jbeech]

I'm not looking to start trouble, nor stir up fanboys. Simply put, I've been using pencil and paper for sketching things and then making prototypes with a lathe and mill. When it works, I have parts made in production quantites with CNC machines. While I have resorted to AutoCAD when necessary, it's really not the tool for 3D and a friend will usually convert my sketch using his 3D package but this is becoming awkward as volume ramps up. Hence, I now find myself investigating a 3D CAD package.

I quickly zeroed in on Solidworks as a suitable package but also found Alibre Pro seems to be well regarded. An important advantage of the latter is price, but saving money is soon forgotten if the tool is awkward and not efficient. Consequently, I figured who better to help me choose than folks familiar with these tools?

My parts are simple, and my assemblies don't generally exceed 100-200 parts (and more usually are 15-30 parts).

Frankly, $1500 versus $5000 is significant so what makes Alibre Pro less suited to my needs than Solidworks?

Rgeards,

 

[tygerdawg]

Nothing. AD is a fine package for much of the 3D design regime. It is not as feature rich as SW, but it doesn't really need to be. I'm a SW user at the moment (part of my reseller agreement provides me with low-cost SW). But I have used AD extensively in the past also. In fact, I have proposed to three separate companies that they purchase AD as a means to fill a need for suitable low-cost parametric solid modeller. Each time it was accepted and multiple seats were purchased.

There are many differences and each package has foaming-at-the-mouth belligerent adherents. I haven't touched AD since...ummm...version 7 or 8?...so my info may be out of date. But this is a couple of the "typical" kinds of differences I noticed. SW will give you an entire page dialog to set colors of your selections, layer upon layer of complexity suited to CAD Guys who are immersed in SW all day, every day. AD did not, or only gave a couple of color schemes. SW has some powerful surfacing functions (to help it compete with UG & Catia, I presume), but AD strictly limited themselves to STEP format solids modelling. If you're doing basic machine design, you're probably not doing surface modelling anyway. Essentially SW is premium, feature-rich, with strong support provided by an expensive reseller network. AD's business model is lower cost with less features, online support, but still very functional for most "orthogonal part" designs.

TygerDawg
Blue Technik LLC
Virtuoso Robotics Engineering

http://www.bluetechnik.com

 

[swertel]

I will concur with TygerDawg. If your parts are simple, prismatic milled or turned parts, then Alibre Design will work fine for you. If you end up doing consumer products with curvy forms, then you should look elsewhere.

--Scott

http://wertel.eng.pro

 

[jbeech]

When you speak of surfacing, I presume you mean for molds? Click this link and scroll about half-way down to see an example of the kinds of parts, which we injection mold.

http://www.genesishobby.com/Products/AUD22601/Default.aspx

As for swoopy consumer products, here is a link to an example of one of our swoopy parts:

http://www.genesishobby.com/Products/AUD1016/Default.aspx

. . . is this difficult-to-impossible to create in AD versus SW?

Thanks in advance for the thoughtful responses.

 

[jbeech]

I forgot to ask, but another consideration is how do I interoperate with suppliers if I elect to use AD instead of SW?

For example, for parts I expect to be CNCed, will I give them a .STP or IGES file (and which is better for the purpose?). I presume they will be able to open it with SW, but more importantly, what if it's necessary for them to edit it? Or must I, if dealing with a CAM shop which uses SW, resort to SW as well for convenient interoperability?

In short, when I visited the Design2Parts show in Orlando a few months back, all the vendors said, "Send us a SW file!" and in my inexperience, I neglected to wonder if they could accept a file output from a competing product like AD instead (or if it would becoem a pain in the rear to do this).

Finally, and this is a sideways step in the conversation, do any of you have anything to share vis-a-vis a product called KeyCreator?

 

[swertel]

http://www.alibre.com/success/gallery.asp

Look at Alibre's gallery. It can model your helicopters, but it won't be as easy in Alibre as it would be in Solidworks.

--Scott

http://wertel.eng.pro

 

[berkshire]

jbeech (Aeronautics)
AD also has a CAM program associated with it.
I do programing for a CNC router that uses a program called Toolpath. Alibri Cam enables me to write Ready files that can be loaded straight into their machine.
B.E.

 

[swertel]

1) Just send your machine shop a step file. They will be able to open it in their CAM package and create the code from it.

2) Even if they use CAMWorks (embedded in Solidworks), they can still open STEP files and generate tool paths.

3) Do you really want you manufacturing supplier to change the model on you? How do you handle release control and revision tracking? FYI: I consider it better to give my suppliers "dumb" solids than native geometry. With all the direct editing tools built into parametric CAD programs now, they'll still be able to make changes if they need to.

4) Any shows I've been to, all the vendors say "Send me a SW file." That's just them buttering up to the largest CAD userbase. It's really no more difficult to send a STEP file as it is a SW file. They probably won't be able to use a native Alibre file, though.

--Scott

http://wertel.eng.pro

 

[jbeech]

swertel wrote: but it won't be as easy in Alibre as it would be in Solidworks.

Why do you say this? Due to my inexperience, I don't have a clue of what process or steps in creation will be more diffcult with one tool versus another, which is the orignal intent of the query. Can you share with me specifically where it will be more difficult in AD vs. SW please?


Further to swertel:
OK, so sending them a STEP file is likely going to work and also resolves security issues (I hadn't thought of that). Also, what format is a dumb solid?

Thanks a bunch guys!

 

[tygerdawg]

jbeech, here's your 10-second tutorial "solids modelling versus surface modelling":

Solids Modelling is manifested by "sketching" a 2D shape on a sketch plane (think "AutoCAD"), then extruding that 2D shape into a 3D solid. Then repeat to add more / subtract less solids volume from that part. Then repeat for more parts and clump them together to make an assembly.

Surface Modelling is sort of like using CAD functions to blow a big bubble out of a mouthful of Bazooka bubblegum, then push poke twist and otherwise distort it into the desired shape. Then repeat etc.

TygerDawg
Blue Technik LLC
Virtuoso Robotics Engineering

http://www.bluetechnik.com

 

[swertel]

Part 1:
To elaborate on TygerDawg, and hopefully clarify differences between Alibre and Solidworks as to why one would be more difficult.

Alibre does simple prismatic geometry very well. Consider it simple turned (lathed) cylindrical geometry or 2.5 axis milled geometry. If you get into 3, 4, or 5 axis milling, Alibre is not as mature as Solidworks and therefore doesn't have the feature set to create the geometry easily. This has nothing to do with solids modeling vs. surface modeling. This is a feature-to-feature comparison and options available to make a robust model. Alibre can do it, but it will take you more steps to accomplish the end result and the model may not be as easy (or even possible) to modify.

Some specific examples:
* Using sketch geometry to drive other sketch geometry.
* Extruding with built in draft or end finishes (like crowns) without having to create additional features.
* Top-down design methodologies (where you use an assembly to drive part dimensions).
* Fillet options.
* 3D Curves

In the case of a helicopter, you are going to be lofting and sweeping a lot of geometry. The lack of constraining sketch geometry to other sketch geometry means you'll have to work out the math in your head to dimension each sketch from an absolute point instead of relative to each other. Alibre's lack of 3D Curves (although just got a boost in 12.1) makes constraining the guide curves for your loft difficult.

To reiterate, you can do it in Alibre, but you may be banging your head against your desk figuring out how to do it. Worse, how to modify it later.

--Scott

http://wertel.eng.pro

 

[swertel]

Part 2:

A dumb solid is any geometry that no longer has the features used to create it. Basically, if you export to a STEP file, once you import it, it is a dumb solid because it can't be modified using the original features.

If you look at the feature tree (Design Explorer in Alibre), you will see things like: extrude, hole, fillet, etc. and you can step through each feature to see how the model was built.

With a dumb solid, your feature tree will only contain one feature (yet all the geometry is the same), and you can't redefine a hole, or a fillet size for example. Well, you can, but you have to use different tools than the hole or fillet command.

--Scott

http://wertel.eng.pro

 

[swertel]

Part 3:

A little more on why a hybrid modeler that does surfacing and solids may be better for your work.

Because when creating surfaces, you don't have to worry about generating a water-tight volume. You want to shape a surface of your helicopter, you can push/pull to your heart's desire with a surface feature. You can create a surface that has a variable radius in the U direction and a different variable radius in the V direction. You can't do that with solid features because they extrude a 2D profile into the 3rd direction. Solids geometry is basically planar and has little aesthetic value. (I'm purposefully avoiding talking about revolve, loft, and sweep features.)

In order to get a surface with different U & V radii using solids, you would have to create a series of extrude & cut features. It is possible, just more work.

But, before you think surfacing is the way to go, I have to warn you that surface modeling is a completely different beast than solids modeling. And, you still need to turn all of your surfaces into a water-tight volume at some point. That in itself often poses its own unique problems.

--Scott

http://wertel.eng.pro

 

[jbeech]

swertel wrote: <i>But, before you think surfacing is the way to go, I have to warn you that surface modeling is a completely different beast than solids modeling. And, you still need to turn all of your surfaces into a water-tight volume at some point. That in itself often poses its own unique problems.</>

You are a gem! I am starting to understand, but you threw me a curve with the last paragraph. Would you please eucidate further?

 

[swertel]

Even in a solids modeling program (like Solidworks), the methodology to model surfaces is completely different than modeling solids. The steps may be the same: sketch, extrude, etc.; but the methodology - or way of thinking/attacking the problem is different.

In solids modeling, you worry about exact profiles that represent the final form of your part. You sketch and extrude to exact & measurable distances.
In surface modeling, you worry about the tangency and congruency of the curves. Therefore, you often end up sketching and extruding a surface much larger than your final product just to get the form correct in the area of concern. Then you do the same thing for the top surface, and bottom, and side, and front, and back, and... And then you need to somehow trim all the extra surface geometry - or extend it - to join all the other surfaces into a water-tight "solid."

To summarize, in solids modeling you model the part the way it will be manufactured. For most engineers, this is easy. In surface modeling, you model the part the way it looks attractive. For most artists, this is easy. The construction methods of a surface model may not be intuitively obvious to an analytical thinker.

I wish I had some images to show you the difference, because it would become apparently obvious. I'm afraid, you'll have to try to visualize something based on the above narrative.

--Scott

http://wertel.eng.pro

 

[swertel]

Matt is a Solidworks surfacing guru. Check out some things that can only be done with surfaces.

http://www.dezignstuff.com/blog/?p=2168

Alibre can do curvy parts.

http://www.cadalyst.com/cad/top-down-design-curvy-parts-alibre-design-tips-11195

But it is more cumbersome and the end result is not as smooth.

--Scott

http://wertel.eng.pro

 

[swertel]

(I gotta stop browsing other content after hitting submit.)

http://www.dezignstuff.com/blog/?p=2023

Granted, this is Solidworks again, but you can see how the same swoopy shape is done both as solids and as surfaces. If it was done as solids in Solidworks, it can be done in Alibre.

--Scott

http://wertel.eng.pro

 

[AdamPeszel]

If this is still an active topic, I have used Alibre, SolidWorks and Inventor. If you do not need to do motion studies or need photorealistic images for customers, go for Alibre. If you need a 2D software, SolidWorks and Inventor come with their own software, however there are inexpensive solutions from various companies. IMSI has TurboCAD for about $120 or DoubleCAD XT which has a free version.

One of my hobbies is model railroading and I have recommended Alibre and DoubleCAD XT due to better costs.