CAD vs modeling software (explaining the differences)

I’m not sure if this is the right section for a question like this, so I apologize ahead of time if it isn’t. Anyways, I want to simply and clearly explain the difference between CAD software (Solidworks, Autocad) and modeling software (Blender, Maya, Max) to someone who isn’t familiar with either. I want to avoid a lot of nitty gritty details (feature x vs feature y) that usually get brought up in these types of conversations. Does anyone have any suggestions? I know there are related posts out there, but none of them seemed very concise or definitive in their answers. Sometimes I feel like the distinctions are somewhat arbitrary and meaningless. Any help would be great.


I only ever used 1 piece of CAD software and it was about 6 years ago in High School. It seems that most of the CAD software is more informative like measurements, angles, materials used, etc… and I’m pretty sure its all wireframes (could vary from package to package though). CAD seemed harder to use, but then again, I was 15 :o

The simplest I think I can explain it would be that “MOST” modelers are surface modelers and most CAD are solid modelers. In CAD objects are generally defined by solid shapes (and the adding and subtracting of other solids (i.e. Constructive Solid Geometry (CSG)). The software more or less believes the item has volume. This is largely so you can do structural and stress like analysis on the components you design.

Most “modeling” software (like blender etc.), the objects created are more or less skins representing a solid surface. The items created do not actually have volume. If you were to perfrom a cutaway on a primitive, it would be a hollowed out shell. You could then patch over the cut-away section to make it appear solid.

There are many other differences but I think that would be the biggest.

well, I’m far from an expert…so sorry if I lack precision
The most important characteristic, is, to me:
Blender is “fun”, CAD is “boring”! :slight_smile:
Now, a little more serious, like CAD software, models in this type of
soft are defined by “math/volume” as stated above, so, they are “real”, you can
link them to CNC machines for example, and make them exist.

CAD programs are used by engineers and draftsmen, Modeling programs are used by artists and animators.

CAD isn’t related directly with 3rd dimension. There are for example CAD apps that are 2,5D or just 2D because - in depeche mode - CAD soft is used for creating technical specifications.

I don’t know if you’ll get the point, but, me, I’ve learned how to use “depeche mode”?! :slight_smile:

More specifically, CAD doesn’t have to have the 3rd dimension - when you consider what it is for: the accurate description & communication of real-world, man-made objects. This description can often be (and mostly still is) depicted in two dimensions because it has historically been communicated via sheets of paper (drawings.) However, this is changing, as (mentioned above) 3D models are now commonly transferred electronically and fed directly to the manufacturing equipment (CNC - computer numerical control.)

What Orinoco said,

CAD programs are used by engineers and draftsmen, Modeling programs are used by artists and animators.
is accurate, but could be “fleshed out” as:

CAD programs are used by engineers and draftsmen to create geometry & visual output that is dimensionally accurate for the purpose of documenting reproducably fabricated objects. Modeling programs are used by artists and animators to create geometry and visual output that is graphically accurate for the purpose of creating viewable content.

Oh, and for the record, with blender’s STL i/o, CNC’d models are very doable. I’m working up a VW Beetle presently for my son’s pinewood derby entry. (He’s a big “Herbie” fan!) :slight_smile:

Well not to be nitpicky here but that’s really just one side of it. Architects (or Architectural Engineers) create viewable content and animations (fly throughs) using CAD for the purpose of presentations. MEs do the same from time to time for product literature and such (we used to do that all the time). If someone is hell bent, they could probably do anything they wanted with either type of tool, I remember seeing a model of Micky Mouse done in AutoCAD quite a few years back… I thought the guy that did it was insane.

Yeah, I think what we’re talking about here is primary usage. While such illustrations can be produced using AutoCAD or Inventor or Revit… most of the time the geometry is exported (usually to VIZ) for these tasks. I remember setting up and outputting a bunch of “slides” in AutoCAD (remember those in AutoCAD? That’ll date you!) in order to have a rudimentary wireframe animation to illustrate a lever’s motion in a particular application. Took like most of a morning to pull off - and the results were iffy at best. Talk about insanity. :eyebrowlift2:

Conversely, just because you can make dimensionally accurate models in blender (or export STLs for a CNC op) doesn’t mean its the best tool for the job (yet.) :smiley:

Thanks guys. You confirmed some of my initial feelings and clarified other issues. I like the idea of “primary usage,” as it’s a relatively easy concept for someone with no experience to grasp. Plus it conveniently sidesteps all the exceptions (e.g. animations/organics in CAD, engineering/architecture in modeling software) that inevitably arise, since there will always be people who use software in a way that wasn’t intended.

I don’t see what the British music group Depeche Mode has to do with this…:confused:

As well as line drawing you can dump out in blender - the advantage in draughting is you can do cool walk throughs - an example of a room I’m considering using for a short film, this is a concept piece for the production designer. Blender rocks


Being an AutoCAD user (its my job) it is where I first delved into 3d. AutoCAD is capable of doing the exact same things that 3d modeling software can…its just a different way. Your models don’t need to be solid…it works best for buildings though. For complicated objects you draw the basic wire frame then have CAD fill in the space between with mesh. AutoCADs 3d functions are made to do precise models. It isn’t something you would do characters in that for sure, but you could. The screenshots are a foosball guy I made in CAD. The first being the wire frame and the second being the mesh.

I don’t know is if anyone’s mentioned yet the fundamental difference between the two applications.

I’m no expert, but I have been researching this stuff for quite a while now for some secret personal projects that I’m going to do in the near future. :stuck_out_tongue:

The two applications use two different approaches to ling: CAD uses solid ing., while CG software primarily uses surface ing.

The difference is that solid s have volume, while surfaces obviously don’t.

But then again, I guess you could use Blender to operate a CNC machine via the STL exporter, something I have been considering as an option.

Well, like I said, I’m no expert; this is just what I have managed to glean from my research, hope it helps. :slight_smile:

Also, on a related note, I was about to post about avoCADo, an open source CAD app.

Looks like it has potential.

Its growing and needs developers, and people to spread the word.

So if you want a viable free alternative to high priced CAD software, this looks like its worth a shot, if enough people become involved.

It could be the Blender of open source CAD. :cool:

Yeah, what Laughing Cheese says is true (solid models verses surface/mesh models) but it doesn’t accomplish the original request of the thread - the average person’s eyes would glaze over when you said this. Thus, it has to be broken down to purpose & use, as has been done effectively above.

Morokiane, not sure how long you’ve been an AutoCAD user, so take this with a grain of salt… but AutoCAD actually does 3D much better using Solids and Boolean operations rather than meshes. Extruding/Revolving/Sweeping closed polylines gives you solid entities, which can then be further “chiseled” away with chamfers, fillets, slices etc. to get to your desired end model. While not history-based, and thus not editable, its quick and effective for most stuff. XREF works quite nicely in creating assemblies of solid parts. Additionally, the capability is in there to auto-generate all your 2D views in the drawings (paperspace) from these solid entities & assemblies. This is the automation I was after when I set it up years ago (back on R13, believe it or not.) I hated having to manually change 3+ views for every little change that was made.

But then along came SolidWorks and I never looked back to the “Dark Ages” of Acad. :smiley:

I’m a Autocad guy and have been since release 17. Autocad will definitely do 3d but definitely not as efficient as other 3d modeling software.

So here’s the real question. What software would be easier to transition to for a person with nearly 20 years cad experience? I’m looking into 3d printing as a hobby buy I don’t know where to start

I’d look into rhinoceros, a little expensive for hobby but awesome cad modeller that also has nice poly retopology tools. Definitely superior tools to blender for hard surfacing.
For organic/semi-organic shapes you might try combining blender and rhino. where you could export subD/quad based mesh to rhino and there convert it to subD and then to cad for nice cad operations (booleans, trimming, fillets etc…)