3D CAD software - what do you use?

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A mention for OpenSCAD. It is quite different from most, the model being created writing scripts to build by extruding or rotating basic shapes or imported 2D shapes from DXF files.

It won't be for everybody but it is very good if you want to lay out repeat copies of a shape. Being script based, your model can also contain 'if' conditions which can be used (for example) for creating both the printable (STL) model and a 3d assembly preview from the same model.

I have been using it since 2013 for 2mm scale models. I also did a 3d preview of our new fitted kitchen with it.

I'm also an Alibre user and I'm sure you have seen I make what I draw. If starting out from scratch again I can see the temptation to go for something free but there is always the niggle in the back of my head that says it won't stay that way for ever, you may get a lifetime licence but whats to say you will get a lifetime of updates if they change their terms or could you even download onto a new computer in the future? At least with a paid for one you get updates, can use where and on what you want and help is readily available.

All very complicated and a big jump into the dark for a new user

I downloaded gigabytes of stuff and tried it out before opting for the freebie Designspark Mechanical

**LINK**

GL

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For anyone needing to quickly start designing simple 3D items (or adapt existing designs) for 3D printing - then Open SCAD is a great solution. I have designed and printed items for workshop use, as well as modified other (existing) designs from Thingiverse to suit my needs - and I did so within just hours of downloading SCAD.

These have include vacuum hose adaptors, clamps, tool clips and Dremel parts. I don't think anyone could get going anywhere near so quickly in the 'Pro' 3D CAD systems being discussed here. They need a lot of time invested in them - whereas Open SCAD offers a much simpler (almost step-by-step) access. I may never design anything very complex in SCAD myself but others will do so - and I can then use and adapt that work.

It is very simple to get started in SCAD and since everything is text based there are no issues with learning mouse controls or user interface. It is also very logical and precise in use. If I ever need to teach my Grandson 3D 'design' (for 3D Printing) then I would certainly choose SCAD in preference to any 'mouse' controlled CAD system. It would be much easier to teach step-by-step (staged) design and as the syntax is based on 'C' - it would also help provide him with some understanding of programming languages too.

However, it was clear SCAD was not going to replace TurboCAD (2D) for my engineering drawing needs and whilst I am fairly proficient now in TC 2D - the attractions of parametric design in 3D and being able to easily move these 3D designs to 2D drafts have persuaded me that the effort required is worthwhile. As I become more familiar with SE, even drawing in 2D is becoming much more attractive. Just sketch an outline (no need to be precise), define some relationships and then use 'smart dimensions' to correctly size the part - so it is a better/easier way to draw 2D as well. I can then take a little more time with the 3D aspects but it's already very clear that I will now transition fully to Solid Edge for my drafting work.

Regards,

IanT

Edited By IanT on 19/05/2020 09:36:54

Many thanks for the comprehensive and helpful responses - I will have to do some studying, not to mention downloading!

The three pics I put up in an earlier thread on Solid Edge, were merely to show just a part of what it is capable of. I usually build what I draw [ not models.. gave up on them after the aborted attempt at the Renk gearbox ] although I had no intention of trying to build the Liebherr 600tonne crane block, Siemens motor or the Forkhardt chuck. They were from earlier projects for a third party.... non model related. And merely to show the level of programme it is [ and even they don't amount to a hill of beans compared to what it is capable of doing when required.

The program, or rather application, that I use is called Onshape. The main reason I use it is because it has an Android application so I can use it on my tablet (I dont use a PC or laptop anymore).

The main selling feature for it is that it is entirely web based so for a PC or laptop there is no software, you just log in on there website and it's all done online. Obviously this means you need a good internet connection, but on the flip side your not storing however many Gbs of data on your PC and you dont need £1000 worth of machine to run it. It runs perfectly well on my 6 year old tablet, and I have also run it on a pretty standard PC at work.

It is free to use but your drawings are public, I was apprehensive about this at first but as long as your not doing prototype invention sort of work it's not a problem, worst case call it John Smith's drawing #1.

You draw in 3D, make individual parts and mate them together in an assembly if required. A 2D drawing can be created from the part (PC only option). I find it pretty straightforward to use, I had previously done a small amount on Soildworks and found it not too dissimilar.

Worth a look if any of the above features suit your needs

I use CATIA, which is virtually the aerospace and motor industry standard. Unless you have a truck load of cash or like me have access to it, you will not be going anywhere near it. However Solid Edge comes very close to it in terms of functionality for mechanical design and if my CATIA licence ever goes the proverbial I will replace with SE. I already have it running on my laptop along with Fusion 360. High end systems tend to be logically set out and easy to use after a small amount of training. After all we wanted our engineers designing product not wasting time working out how to use the system. With CATIA we have taught people who have no engineering knowledge or experience to be modelling parts and assemblies within a couple of a days. I have a couple of friends using SE now and they are getting on just fine, one has never used CAD, the other only Autocad. Investing a little time now will pay dividends for that big project later on. By the you do not have to save to the cloud with Fusion 360. If you use the export command you can save to a folder on your hard drive.

Dave

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Tony asked about software for printing and I pointed to FreeCAD and a tutorial showing how objects are developed from sketches into 3D. Various alternatives have been mentioned, and plenty of nice photos of what can be done but no-one has explained the actual workflow. I'll use FreeCAD to make a box and Cura to print it.

First sketch a rectangle and pad it to make a 3D block

I won't describe the detail, but the block's corner are filleted, 4 screw-holes pocketed, and then the block hollowed out by pocketing a third sketch. The result:

So far the object is just a FreeCAD model. The next step is to export the model from the File menu, top left. FreeCAD Export supports many options, but most 3D Slicers (which instruct the physical printer), work from STL. Select STL Mesh and save the file.  We're done with FreeCAD.

Start Cura, or other slicer and open the STL file exported from FreeCAD.

Next step is to use the STL file to print the model. It's not done by FreeCAD. Instead a slicer is needed, this demo is done with Cura, which is free. The slicer translates STL into a series of layers 'slices' that are extruded one at a time by the printer to build up whatever walls and holes are needed to create the wanted shape. The slicer is told which printer is connected and controls type of plastic, nozzle diameter, percentage infill and other manufacturing parameters.

As a sanity check slicers usually display what they think the object looks like (the shape and size should be identical to the FreeCAD model, but things go wrong), estimate print time, and how much plastic will be consumed.

FreeCAD and Cura cope well with simple engineering objects like boxes and parts. FreeCAD's not so suitable for making curvy artistic objects. The type of model wanted may influence product choice.

Dave

Edited By SillyOldDuffer on 19/05/2020 14:18:09

Tony

Given the complexity of a drawing package the best place to start is investigating what help and tutorials are available.

Doesn't matter how good the program is or how great other people find it if you can't learn to use it.

My experience. Your Mileage Will Differ.

Tried to get on with Fusion about 3 times now and got pretty much nowhere fast. Why? No proper printed manual or effective printed course guides about. Call me old fashioned but I find on screen tutorials hopeless.

Leaving aside the question of how you watch a tutorial whilst simultaneously working with the program I find the difference between the pace I want to work at and the pace the tutor talks at insurmountable. Usually the tutor goes on about the, to me, obvious at considerable length then glosses over an important issue in about four words leaving me yelling at "Hang on, go back." at the screen.

Never yet found a tutorial with the ability to flip back 50 pages, then 20 pages and finally use the index to go forward to finally nail something in proper context.

I splashed out on the Autodesk Fusion 360 Black Book 2nd edition hoping that it might be "the missing manual" as Apple folks are wont to say. Worse than useless. Its neither a manual organised so you can find stuff or a tutorial so you can learn about things. Basically the worst of both mashed together by an author who hasn't used the program in anger. Should have twigged when I saw a long list of othe similar books he'd done. Classic rent-a-quote expert.

A quick look at Scribd suggests there are a few more books on Fusion out there than when I purchased nearly 18 months ago. When it comes to expensive books I find Scribd a useful online substitute for looking at several options in a book shop and deciding which one to buy. Doesn't always wok but beats ordering blind off t'net.

Found some fairly decent short course based offerings out there but all seem aimed at the school market. "Lets make a key ring! Fine, done that, now what!".

Fusion having recently changed significant aspects of the user interface hasn't helped.

About to find out how I get on with Sold Edge. £200 on a 1 TB SSD and 16 GB of extra memory so my mid 2010 MacPro has the headroom to run Virtual Box, Windows and Solid Edge. What was that bit about free CAD! Unfortunately mine is one model too early to Bootcamp Widows 10.

Another important issue is whether you can learn something in isolation or need a reason to do it. I'm heavily in the need a reason camp having used MiniCad, now Vectorworks Mechanical, in 2D for "not telling you how long" I can pretty much make the 2D side dance despite a few objections. But the mechanical side hasn't been updated for a decade or more and paying £1,000 to upgrade merely so I can move on to a later version of MacOS isn't happening. So hopefully SE 2D will give me a transition of what I use now with 3D coming later. We will see.

I find it hard to do the beginner steps in a new thing when I can get to the same place doing things the way I've always done them. Jam tomorrow, or more likely next Monday, is a great idea but I have a pot on the table next to my knife right now. OK its a smaller pot than yours but I want my tea now! Seems to sum up the way I think.

Best of luck.

Clive

Is that true Dave? My understanding is Fusion works on a local copy whilst a part is being developed but saves are to the cloud unless the link is off-line. It doesn't fall flat on its face if the internet or servers go sick. But off-line working is only a short-term expedient, 30 days max from memory, after which Fusion must resynchronise data with the cloud. I don't think Fusion can be used completely off-line and in private - it has to phone home periodically.

It can export files, but that's for local back-up and transfer to other products, not a way of permanently avoiding the cloud.

Fusion being cloud based is what I like least about it. It's worth the risk, after all the bank keeps my money in the cloud too...

Dave

Barrie, no problem.. I never thought that for a minute Dave Smith , you mention Catia, have you ever used Solid Edge's big brother NX.[ got a price tag to match it's power, fine if you want to sell the house and move into a cardboard box ] In fact , talking of the car industry Daimler Benz had the biggest migration in Cad history when they moved from Catia to NX. Did start to try to learn NX but way, way beyond me. Solid edge is more than enough for me... in fact, I don't think I have ever used anything like it's full capabilities. Still I mustn't derail the thread with idle chatter. Good luck to all who took up the Solid Edge offer, Keep practising...and you will be up to speed fairly quick.

One thing you might consider, in general terms, is whether you are likely to want to import other file formats and whether the candidate will actually allow that in the formats you need..

For example, I looked at MoI which seemed quite attractive but the list of import file formats was rather limited. No STL for example.

I have tried to get on with Fusion 360 but am now really tempted by the community version of SE, its minimum hardware requirements means I need to upgrade my PC or get a new one.

Lots hard disks and Win 10 on an SSD etc but I only have 4GB ram (DDR3) and a 3 Gbyte G3220 Pentium with onboard graphics, is it worth spending money on ram or should I start again?

Ian P

Ian P, Looking at those specs, I would be tempted to start afresh. SSD drive is good, but the rest.. hmmm. FYI Solid Edge is a single threaded app which means it wont take advantage of a Cpu with lots of cores. Clock speed is the name of the game with SE. 8 Gb ram should be your minimum [ DDR 4 ] all depends on the size of your data sets. Will work fine with onboard graphics but a dedicated Gpu is best... again its tied into the data set size. Data set size is not just related to the number of individual parts in an assembly but also to the complexity of the geometry ie fillets, chamfers ect. Good luck,

Large monitors (in terms of pixel count) put a lot of extra demand on the graphics requirement.

So a '4K' monitor (or worse 2 or more of them) will hit the graphics capability hard.

A single screen of modest pixel count is more likely to cope tolerably with integrated graphics.

STL is not a good format for imports, aside from not defining what units things are in, if you have compound curves (e.g. curved fillets) they become massive because every surface is converted to small triangles.

This means they can't sensibly be back-converted to any other type of shape.

For example the rather complex base for my mirror cell is 2.8MB in Alibre, but 68MB as an STL. It's possible to use smaller angular resolution (I use 1 degree) but on larger parts like the base you get visible facets if the step size is too large.

Neil