2D vs. 3D cad, is there any point to continuing with 2D?  Rambles welcome. - Page 1
Forum section: electronics / general

author: apblog
author_rank: Regular Contributor
timestamp: December 28, 2017, 04:15:48 pm
content: Hi Everyone,I'm thinking about buying Draftsight for $99 while it is still cheap. I was wondering if you guysthink it is a good idea to invest money and time into 2D cad or if I should somehow go straightto 3D.I rarely use CAD, either for hobbies or work. For work (I design circuits and PCBs) I use it to communicatebasic dimensions and hole locations to the mechanical engineers, who do the actual manufacturingdrawings. I usually use some free-ish version of Draftsight and output DXF.For hobbies, I use it to make basic drawings of the wood boxes that I build. Draftsight has been nicefor that because I can draw profiles of things with crazy angles, and convert the angles into side-lengthswhich I use for marking the wood for cutting.I learned basic Autocad in 1989, so I'm somewhat comfortable with 2D.I've tried Sketchup a few times but I hated it because I like to input things "by the numbers", not by trying to draw around in 3D space with a mouse.Recently I saw some very cool 3D exploded assembly drawings made with Inventor, which got me thinking about the possibilities of 3D cad.I think it would be very nice to be able to fit virtual parts together in 3D to check fit.3D would also be really nice for creating/editing STEP models for Altium. Right now I rely on whateverdownloads I can find. And work is starting to ask for 3D PCB models more often now.And with 3D cad I think it would be easier to draw boxes with compound angles -- by which I mean a surface that is angled in more than one dimension.Anyway, consider this an invitation to ramble on about how you actually use 2D and 3D cad programs and what value you get out of them.Thanks!

author: ebastler
author_rank: Super Contributor
timestamp: December 28, 2017, 05:02:18 pm
content: Quote from: apblog on December 28, 2017, 04:15:48 pmI won't offer much advice on 2D vs 3D; others are certainly better qualified. Only one comment on that front: With 3D printing becoming an increasingly practical tool, and CNC machines fed directly from 3D model data an established reality, I think there is a lot to be said for 3D CAD.Main point of this post: Please be aware that the $99 offer is for thefirst year of a subscription; subsequent years will be $149/year. There is the alternative offer of a permanent license (with updates during the first year) for $299.

author: Pitrsek
author_rank: Regular Contributor
timestamp: December 28, 2017, 05:04:07 pm
content: Take look at Fusion 360 - free for home use, plenty of info on internet/youtube. I quite like it.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: December 28, 2017, 05:09:28 pm
content: 3D is really useful for building large assemblies/systems. It is often useful for specifying parts to vendors, and necessary if 3D printing is the manufacturing process. But for single simple parts like those most often needed by hobby persons 2D is fine. As you are finding, there is a large skill set to learn in going 3D, and in general the tools are more expensive, both hardware and software. I think there will always be a place for simple 2D even with as the tools for 3D become more easily obtainable.

author: ChunkyPastaSauce
author_rank: Unknown
timestamp: December 28, 2017, 05:21:19 pm
content: Second vote for Fusion 360. Also I hear about OnShape a lot.

author: mc172
author_rank: Frequent Contributor
timestamp: December 28, 2017, 05:41:02 pm
content: Quote from: CatalinaWOW on December 28, 2017, 05:09:28 pmI don't agree with this at all. So what would you use for small assemblies?Even a part with not many features such as a 90 degree steel bracket with some off-centre screw holes becomes complicated when trying to draw in 2D CAD. 9 times out of 10, you'll get the holes backwards. It probably won't matter but there will be a time that it does.I can't think of a single argument for the case of 2D CAD. If you are modelling something simple enough that you can model it with 100% accuracy (i.e. you are 100% sure of which features are projected and which are hidden for a projection, which way round they are etc.) in 2D CAD, you likely don't need anything more exotic than a pen and paper, ruler and compass.AutoCAD does do 3D but it is so clunky and it seems to get confused when you model something fairly complex like something with a few hundred holes. I like the command line entry but proper 3D packages are lightyears ahead.Most 3D packages are made to be deliberately intuitive. For example, SolidWorks has a feature called Instant 3D, whereby you can draw a circle (for example) and physically pull the circle up or down to create a cylinder. It's really easy and there are lots of free videos and support forums out there if you get stuck.You can of course input by precise numbers.The fancy schmancy stuff that people do with surface modelling, animation of machinery, etc. is irrelevant. It really is easy! Start with something simple. Model a box, put a hole in it, move the hole, change its diameter. Put another hole on another face.If you need to model a driveshaft you can model it as if you were machining it. You can start with a big piece of round bar and remove bits as if you were machining it in a lathe. Just go for it! Once you are able to model something in 3D, you'll use your 3D CAD package much more than you thought you would. I even modelled my house...

author: ajb
author_rank: Super Contributor
timestamp: December 28, 2017, 05:54:35 pm
content: Any real mechanical design I do is generally in Fusion, but I still use AutoCAD LT (which is strictly 2D) for various things. Even the really good 3D MCAD tools generally can't hold a candle to AutoCAD when it comes to doing 2D drawings, and sometimes a 2D drawing is what you need.Some of the things I do (in 2D) in AutoCAD:Cable Assembly drawings -- the amount of work it would take to do these in 3D is nowhere near worthwhile, unless you have something like Inventor where you can design harnesses into your MCAD and have it spit out drawings for you. But at this point I have all of our common connectors in a template file as blocks, so mostly I can just copy/paste/tweak for any new drawings I need to make. Way easier than having to manage a whole load of 3D assemblies for this purpose.Tricky ECAD symbols -- Altium's drawing tools are horribly crude compared to AutoCAD's, so I will occasionally draw tricky shapes in AutoCAD and then import them into Altium.Examining manufacturer CAD files -- many manufacturers provide DWGs or DXFs, and if the dimensions I want aren't printed on the PDF I can usually get them out of these files. Even if a 3D model is available, it's usually faster to look at the DXF.Drawing cleanup into/out of 3D CAD -- the 2D files you get out of 3D CAD aren't always great--often having duplicated lines, splines instead of arcs, etc. This can be a pain if, for instance, you have a 2D DWG from a manufacturer and want to make a 3D model from it. 2D CAD can be used to clean up the file, or strip out everything but the actual geometry you want to import into your 3D CAD.2D CAM prep -- If I have a 2D output from a 3D CAD program that I intend to laser cut, for instance, I sometimes move it through AutoCAD to do cleanup (as above), or array/nest parts into a sheet.Precision sketching -- Things like layout out panels, where I want to move things around a lot, I can do way more quickly in 2D than in 3D. Laying out furniture in a room would be similar.As a common denominator and information sieve -- Sometimes the only way to get information from point A to point B is through a DXF. Sometimes this is a pain, but often it's also a good opportunity to pare down to just the information you want to translate from one point to the other. For instance, if I have a PCB in Altium, and I want to transfer the hole locations to an enclosure panel, I could export a step file from Altium and then import it into Fusion, but if you've ever done this, you've seen how horrendous Altium's step files are, and how time consuming it is to deal with them in Fusion. Instead, I could export the PCB outline+holes as a 2D DXF, clean up the layers if necessary in AutoCAD, and then pull in the 2D DXF as a sketch. (This way I can also pull in information on mechanical layers if necessary.) Or going the other direction, I might need to match PCB features to a housing. I could import the step file of the housing into Altium, but aligning PCB components to 3D bodies is a pain in Altium, so it might be easier to create a 2D drawing of the geometry I'm concerned with, import that into a mechanical layer, and then do my alignments in 2D. (At least initially, once I'm fairly sure it's right I can do a full 3D workup to verify, but this way I don't have to do a lot of time consuming back and forth in 3D.)There are other uses as well, but those are the important ones from the top of my head.Aside from 2D CAD, another useful tool is a good vector graphics program. We use Corel Draw for laser cutting/engraving with our Epilog, but it can read and write DWG/DXF, so sometimes it's useful in the CAD process--for instance, if a manufacturer only provides a PDF of a drawing, I can pick the PDF apart in Corel, save the geometry I want as a DXF, clean it up in AutoCAD, then import it into Fusion to create a 3D model. (You can xref a PDF into AutoCAD, but this doesn't always work super well when you want to extract geometry.) It's also useful for things like front panel legends or instructional graphics. Inkscape is probably a good FOSS solution here.

author: rrinker
author_rank: Super Contributor
timestamp: December 28, 2017, 09:26:06 pm
content: 3D has always seemed to feel "tacked on" to AutoCAD. In that same 1989 timeframe, I, as the 'computer guy' was sent to class with my company's drafting team to learn CadKey. CadKey was native 3D already at that time, which is a good part of why we went with it instead of ACAD. I used that a bit on personal projects but I wasn't doing much that required CAD. I still had a student copy of ORCad I used for electronic projects. A few years later I used PC Draft-CAD, a 2D program, for some around the house things and model trains. I haven't used a general/architectural CAD program since. I have a specialized 3D CAD for model railroads, although it also can be used in a more general manner, as I used it to design my workbench, and I've been using KiCad for electronics. I did install a copy of 3D Sketchup because I was going to design something for 3D printing, but I haven't gotten around to playing with it to be any good at it.Bottom line, either way works for me, although I am more comfortable using native 3D as opposed to making a series of flat drawings and then tilting them in to place for a 3D view. At the same time, I am fairly good at looking at 2D blueprints and visualizing the finished object without a 3D view.

author: jolshefsky
author_rank: Regular Contributor
timestamp: December 28, 2017, 09:36:34 pm
content: I have bumbled along with 2D CAD for a long time now. I'm not a particularly good mechanical designer, but I can still dig in and make smart 3D designs with 2D CAD so I can send them to a machinist for fabrication (I use both a manual shop and a CNC shop). For 3D—specifically 3D STL files for 3D printing—I get by with OpenSCAD which is more of a 3D programming language.But I recently sawMicah Elizabeth Scottmodify a 3D drawing for her "Tuco Flyer" project on YouTube and was blown away. She had set up all kinds of rules (minimum thicknesses, minimum distances between parts, specified radii on corners, etc.) in SketchUp I think which let her make changes by sliding things and received warnings in all kinds of detail. (The videos are often very long and I can't find it right now ...) I do think there's merit in learning a new tool, but I suspect I'd continue with the old ones for a long time regardless.

author: hli
author_rank: Frequent Contributor
timestamp: December 28, 2017, 10:25:01 pm
content: Quote from: apblog on December 28, 2017, 04:15:48 pmWhy don't you use the free version? Do you really need thefeaturesof the professional version?Quote from: apblog on December 28, 2017, 04:15:48 pmI use both. 3D CAD for anything that gets 3D-printed, or where you need to get a sense of how it looks in 3 dimensions. 2D gets used when the result is used for 2D purposes. Just fired Draftsight up today to draw the outline (with exact dimensions) for my new workbench (which goes into a corner and needs some specific cut-outs). This will be used to get the board cut properly. Nobody will need a 3D drawing for that.Same is true for e.g. front plates in enclosures. Its nice to draw the enclosure in 3D, but when you design the front plate you do it in 2D (because it needs to get manufactured, or maybe you print it out).

author: Mr. Scram
author_rank: Super Contributor
timestamp: December 28, 2017, 10:35:41 pm
content: Quote from: Pitrsek on December 28, 2017, 05:04:07 pmAs long as people are aware it's a cloud service with all associated qualities and issues. People seem to dislike Windows 10 because it requires giving up a fair bit of control and Fusion 360 requires a larger commitment than that.

author: tpowell1830
author_rank: Frequent Contributor
timestamp: December 28, 2017, 10:39:12 pm
content: In a word, both are significant and useful. I have used Solid Edge, Pro E, Inventor, NX for 3d as well as Autocad, Progecad, Draftsight for 2d drawings and I can't make straight electrical line drawings very well with 3d or make assemblies very well (or fast) with 2d. For engineering at any useful level, I would say learn how to use both and make a reasonable choice as to what to use, when.I will load Draftsight or Autocad to do a quick and dirty 2d sketch to give to someone for drilling(punching) holes in a flat pattern on sheet metal, where if I need to create a sheet metal drawing, I would do it in Inventor and create the sheet metal folds. Layout drawings, electrical line drawings and even simple harness drawings I would do in 2d (notwwithstanding complex harnesses such as I design for the Starliner, Mentor Graphics and NX are what we use there).As far as my favorites are concerned, Inventor and Autocad. I have used Autocad (in DOS) since version 2.2 and started using Inventor in 2005. I started out using Pro E and hated it, and then fell in love with Inventor. Parametric is the way to go, since all you have to do is enter the parameter changes you require in a table and you have a new part. Not that creating a new part is that hard.If you are not using a professional version for hobbies, etc. Draftsight 2d has a free version and Autodesk has Fusion 360 for 3d that I use in my hobbies. Both are very professionally done and are very usable.

author: jpanhalt
author_rank: Super Contributor
timestamp: December 28, 2017, 10:48:11 pm
content: Hobbyist here.Many years ago I got Drawing Board (from a predecessor to Ashlar-Vellum). I then updated to Graphite 6 (also 2D from that same vendor). At the time, its 3D sucked, so I got SolidWorks on an academic license.Its 3D was vastly better at the start, but it got so tarted up with icons and "context sensitive" menus that after 7 years, it was virtually unusable to me. I wanted a program I could think and design with, not one where the challenge was to enter a design. Google'sSmartDrawSketchUp (free version) was good for geometry, but lousy for dimensions and for aligning faces on parts. User blogs helped solve the latter problem.When it went subscription, I went back to simple 2D (Graphite), and it works for me. Of course, I do not need to generate files for 3D printing and do all of my own machining on manual machines (lathe, mill, grinder).If I were doing 3D as a daily job, I could see investing the time into something like SolidWorks, but as a hobbyist with only occasional need, it was not worth the bother.

author: apblog
author_rank: Regular Contributor
timestamp: December 28, 2017, 11:48:38 pm
content: Thanks so much everyone for the thoughtful and detailed replies.I'll probably check out Fusion and take another look at SketchUp. I hadn't even thought of trying to make parts for 3D printing.My biggest problem with most of these cad programs is how much work it is to enter a design. Compared to just drawing something on a piece of graph paper. But trying to submit any kind of hand-drawing for work just gets a bad reaction from people, even if it is just for documentation/communication purposes (not for manufacturing obviously).A few years ago I tried to model a bookshelf in SketchUp and just gave up in frustration that it wouldn't do what I wanted. Which was to model the planks and then assemble them, not just make a monolithic 3d bookshelf shape.Quote from: hli on December 28, 2017, 10:25:01 pmI do currently use the free version. I was just thinking about buying it before the price goes up to $150. But I didn't realize it was a subscription, which makes it less attractive. Looking at the list you linked, I think that "Drawing Compare" would have been very help on one project where I ended up with a lot of different versions.What would have been really neat though is to make sure that dimensions were syncrhonized between the multiple different views that I drew.Quote from: tpowell1830 on December 28, 2017, 10:39:12 pmI got a free copy of Pro E a while back (legitimately), and I couldn't make heads or tails of it...Quote from: jolshefsky on December 28, 2017, 09:36:34 pmOK, that sounds interesting, It seems like sketchup can do more than I thought. I haven't tried it since the initial release.Quote from: Mr. Scram on December 28, 2017, 10:35:41 pmWell that sucks. I won't use cloud stuff for anything serious. It's not's the privacy issue so much as the potential to lose access to my files if the company discontinues the product.However I might give it a look anyhow.Quote from: rrinker on December 28, 2017, 09:26:06 pmThat actually sounds really neat. I love looking at other peoples model train layouts but I don't quote have the interest to get involved myself.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: December 29, 2017, 12:16:13 am
content: Quote from: mc172 on December 28, 2017, 05:41:02 pmPerhaps I should have conditioned this with more statements. Like, if you are already proficient in 2D. And state that if you are proficient in 3D but not in 2D there is no need for 2D ever. But most non-professionals are not proficient in either 2D or 3D. The learning curve to do 3D properly is higher and possibly steeper than for 2D, although that statement is heavily dependent on the specific software, learning environment and background of the learner.I probably shouldn't have placed a limit on assemblies either. 3D is better for almost any assembly, and definitely better if set up properly for parametrics and if any changes become necessary. That said, few hobby people actually do assembly drawings. Look in electronics magazines - you will usually find schematics, gerbers and photographs of the project box as assembled by the designer. No mechanical drawings at all (with the occasional exception of a front panel layout). Same is true about the maker sites and other places that are replacing the magazines. For the little description of parts involved 2D is fine. You example of the angle bracket typical of what I would expect. And those who get confused by the holes in the bracket will get confused in 3D also (but may actually stumble to the correct answer if they rotate and view the part enough).So I would finish be saying that for those who really do need mechanical CAD, 3D and model based design is by far the better answer and likely to be the only one in the future. For those who dabble in this as a side issue for their real interests the investment required to put it to work may be too large for both 2D and 3D, with the 2D investment usually somewhat smaller.

author: jolshefsky
author_rank: Regular Contributor
timestamp: January 02, 2018, 09:38:14 pm
content: Quote from: apblog on December 28, 2017, 11:48:38 pmI'll look more for Ms. Scott's video—I'm not sure whether it was SketchUp or not. Trouble is she does a lot of livestream videos that are typically 3 hours long or more so I honestly haven't watched but one or two of the shorter ones.Edit:OK, I reviewed some videos and found her using Fusion360, but there was one where she demonstrates making a 3D part from concept to build using Rhinoceros 5.0 (aka Rhino), primarily starting just about exactly at the 1 hour mark:I didn't find the exact thing I was looking for, but here's a long trip through designing using Fusion360 with some examples of constraint-based design around 2:22 (I'm jumping around and not watching linearly, so there's probably lots more.):(2nd edit to move irritatingly automatically embedded YouTube ...)

author: apblog
author_rank: Regular Contributor
timestamp: January 05, 2018, 06:22:22 pm
content: Quote from: jolshefsky on January 02, 2018, 09:38:14 pmThanks so much for going to the trouble of finding those videos.The CAD content was interesting, just to watch her putter around in the program, getting a feel for the flow.Cool projects too... She really does it all. "Oh, and I binary-modded the motor driver"... Good thing to watch again if I ever start to think I know something.

author: jolshefsky
author_rank: Regular Contributor
timestamp: January 05, 2018, 08:28:42 pm
content: Quote from: apblog on January 05, 2018, 06:22:22 pmFor electronics-tech related video providers, I usually think I could learn what they're doing—even if it's challenging. Like I think Icouldlearn tube technology like Mr. Carlson, or Icouldlearn how to do high-frequency matched-length data buses like Dave—not that I ever actually will. But she's so advanced it's indistinguishable from magic from my perspective. I can understand the concepts—feeding HDMI video through an object detection sub-system then live-overlaying appropriate sprites—but I have no idea where I'd even start that kind of thing.