I have been using Alibre (now Geomagic) for a number of years to produce 3D models for CNC work and also 2D drawings. I use Meshcam for producing 3D toolpaths and Sheetcam (UK program) for 2D toolpaths.

have a look at my album for some of the results.

Eric

OK Trevor I'll oblige

I have a small 3D part here and it's 64,000 lines long taking in all the fillets etc

I don't think I have that long to live if I have to put that in by hand.

Easiest to learn… that will depend as much on you as the software. There is a learning curve to all these – so if you have access to help from someone, then whatever package they use might be a good answer.

Otherwise, take a look at some free training videos for various packages..

Do you just want to draw single parts, or do designs involving assemblies?

Do you need to be able to import files from other people or from manufacturers? (import/export may be limited on some systems – you may well need to get your files into your CAM software).

Will you need to produce 2D drawings from your 3D designs? (not all systems offer this).

Prices vary enormously, both for purchase and then for ongoing maintenance subscription (if you want to keep the software up to date or get help if it fails).

Can you afford the time and money for a training course ? (If they are available).

You can get free time limited trials of many products – though without access to training videos or some help from a friend, it might still be an uphill task to learn anything useful during the trial period, you'll need to put quite a bit of effort and time in.

I have a connection to a Geomagic (Alibre) reseller, so my advice may well be biased – I think the points I've made are generally valid though when trying to choose a system.

I would say a track link for an excavator is quite complex 3D items

I never got on that well with 2D, prefering to use the drawing board but about a year ago bought Alibre PE and have been very happy with it. You can get a free trial if you visit their site.

J

There is a free 3D CAD available on RS Components website. There are also some quite respectable packages available free to students.

Quite a lot of threads on CAD packages on this and other forums with good and bad advice. However I notice lots of posts mention a package or two they are using and you find they cost more than a decent milling machine even though the post is being made on an essentially hobby forum.

Draftsight seems to be the most popular 2D genuinely free as opposed to short trial freeware. It might be a start.

Edited By Bazyle on 25/10/2013 14:15:10

Draftsight is only 2D so it can't produce the 3D models becky wants.

ViaCAD 2d/3d is presently on offer at $64.99 while MoI is $295 or $89 from Novedge if you are a student or have a teacher friend/relative.

Martin.

Unfortunately this is the state of CAD/CAM right now. It's only recently that there has even been usable 2D CAD for free or within reach of the hobbyist. CAM is even further behind.

Edited By Luke Graham on 25/10/2013 14:34:18

Unless things have changed then I don't think Sketchup is capable of drawing true arcs or circles. I believe they are actually made up of many straight lines to represent these curves and so aren't really suitable for engineering purposes, in my opinion.

Martin.

Martin, that sounds like the sort of thing I know as a "polyline". It is a curve made up from lots of tiny straight lines from point to point.

3D is relatively easy to learn as long as you stop thinking in 2d and start thinking as if the part was in your head or you were actually making it on a machine. Most of them (3D cad systems) are parametric, so the approach is to get the basic shape "sketched" in rough and then add dimensions to fix it in space. Try thinking of how you would start out making a "thingy". You would start by knowing that it needed to be "roughly" four inch long and half an inch thick so you start with a rectangle and add these dimensions. You then need a slot at one end and this is done with a slot shaped sketch (rectangle drawn on the starting face of the thingy) with dimensions added to fix the slot size and position from the end etc. You then think, I need a bolt hole at the other end to attach the thingy to the wotsit – so you use the whole tool to add the correct type of hole by selecting the starting face for the hole and inserting a location point with some fixing dimensions. You then realise that it is too short to reach the end of the wotsit, so you edit the four inch dimension and type six inch instead and the whole thing now looks like it will fit. Save the part, drop into a drawing frame (and if you are lucky it will be able to add the dimensions for you) and print it out. Chances are, the thingy will fit a treat and you have saved a load of time and agro making and moding it!

The alternative would be to keep the thingy you have imagined in your head and try to do all that while measuring and making little fag packet sketches in the time-honoured way – and then making another when you realise it was two inches short or making posh sketches in 2D (but you can't just change the size from four to six inches without a load of messing about).

Mark

Jason, my area is design so I am not fully conversant with current CNC driver technology but I was under the impression that they utilise servo technology these days which would tend to point towards the ability to describe true curved paths rather than the tiny step movements of early stepper drives but I would be happy to learn otherwise. I know that the drives for the "old" Agie wire erroders were capable of holding +/- 3 microns on form from a machine at least 15 years old now but what the form looked like below that level was beyond our ability to measure! Certainly some of the projects I have worked with have nano positioning axis that can repeat to better than a few nanometers but I could not tell you how they interpolate moves from point to point along a curve, how small a line are you thinking?

Mark

If i was going to buy a program it would be alibre design or the equivalent geomagic personal edition, its very similar to early versions of solidworks that i used to use years ago. Don't forget too that siemens do their 2d cad software , solidedge, for free. Its very good and the equal of autocad imho.