3d cad

Discussion
1

So, continuing my adventures into 3D CAD…I downloaded and re-familiarised myself with Sketchup yesterday.

I was trying to model a part I want to laser cut. Drafted it in my usual 2D Design program, and then tried to import as a dxf into Sketchup. For some reason, Sketchup won’t see it as a continuous line, so I can’t push/pull it into 3D. Simpler shapes I’ve had some success with by deleting a few of the straight lines and redrawing them - but no joy here.

This is the part:

CAD.jpg3179×2245 117 KB

So I tried to draw the thing in Sketchup directly. But it seems like Sketchup wants to render circles as n-sided polygons, which makes it rather hard to add fillets. Tried a few third-party fillet plugins (in 2D and 3D) but no joy - it all seems to be back to the issue where Sketchup tries to render circles as polygons.

I think I need a ‘real’ CAD system. But I’m going to have to invest time in learning it, and I don’t want to invest time in learning the ‘wrong’ one. Options I have identified are:

PTC Creo - free version available (Elements). A long time ago I used to use Pro/Desktop, which is probably an ancestor of this. I might even remember some of it when I get going…

Solidworks - no free version, but seems ‘industry standard’? Lots of online training available.

AutoCAD - or is it Inventor? First problem is which piece of software will do what I want! I think there is a free version called 123D Design.

With reference to the cost of the above, I’m loosely affiliated with Sam’s school, and act as a Mentor to her First Robotics team so can legitimately get access to educator versions of the software…

Am I right to drop Sketchup?

Anything else I should be looking at? FreeCAD, anyone?

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I agree Sketchup is very limited.

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I use freecad for modifying existing designs and making my own from scratch.
Never used 3d design software before and im getting good results out of it.
Im able to import .stl files and modify them.
Ready for 3d printing.
It would be very easy to pull that into a 3d object from the flat drawing in freecad.

Gordon

4

As you’ve found, Sketchup isn’t really CAD, so yes you’re right to drop it.

So Autocad is very industry standard and very powerful. It’s also version 20 of 30 year old software so can be rather idiosyncratic.

Inventor is great for more parametric 3D modelling. With that, you can spin a dial for a parameter (ie. radius) and watch your parts stretch and flex in response.

We have actually arranged for free licenses of most of Autodesk’s product range, but a) haven’t followed it up yet and b) don’t have a decent computer to install them on yet.

I don’t know how powerful your own computer is? Inventor and other parametric CAD packages are pretty intensive.

I recommend giving DraftSight a go. It’s basically a clone of Autocad, but completely free and is also pretty lightweight. Like Autocad, it’s a command line system at heart (a relic of Autocad’s childhood when you’d have a text console to control the system and a separate vector display for the actual drawing).

I like this, because it means the software is always being verbose about what’s going on and what options you have in the current command. It also lets you scroll back through the command list to see what you’ve been doing.

The following commands should get you going:

C  - Circle
A  - Arc
L  - Line
PL - Polyline
F  - Fillet
J  - Join
T  - Trim
E  - Extend

And then you can investigate the solid modelling commands. Note that these are “destructive”. The only way to get the source objects back is to undo.

EXT Extrude
UNION
SUBTRACT
SLICE

As well as clicking, you can enter absolute coordinates when asked for a point eg 100,50 or relative coordinates from the last point eg @10,0

F3 toggles geometry snaps
F10 toggles direction tracking snaps
Hover on a geometry snap to get a temporary tracking line
While tracking, type a number to go that many units along the tracking line

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It appears I have a Core i5 processor running at 1.7 or 2.4GHz with 8Gb of memory.

Thanks @gordonendersby and @tomnewsom Some things to get my hands dirty with there…

Draftsight/AutoCAD look amazing, once you’ve learnt all those key combinations. I can see why you wouldn’t want to take your hands off the keyboard to fiddle with a 3D mouse, Tom!

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That’s a meaty enough machine for pretty much anything, so I would experiment.

Autodesk’s software has a massive tendency to bloat, so expect multiple GBs of download for Inventor or Autocad. Draftsight by comparison is only 186MB :thumbsup:

Even if you don’t end up using it for 3D, it’s still a better 2D package than that weird thing you currently use (no offence!)

(I’m also now pretty good at one-handed typing :D)

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Problem with that weird thing I currently use is that I’ve put hours and hours of use into it, and I’m actually rather good at it and quite fast as well! Trying to learn a new package is like going back to school…

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I’ve been playing with https://www.onshape.com/ it’s in the browser no requirement for huge download and a kick ass machine but the draw back it’s online meaning you need to be connected to the internet. Advantage is that the learning tutorial are easy the user interface is great all your stuff is automatically under source control you’ll never loose a change anymore.

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Onshape really does look amazing. I just get a bit twitchy about online software. Will they still be there in 5 years? Can I get my files back in a useful format? etc.

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Onshape looks great!

Aargh! Too many choices…

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At least you have the education link for licensing.
Gives you affordable access to some good pro options.

Ive got no budget so have had to persevere with the freebies and open source options.
But threre are some very useful Applications but they tend to have quirks or interesting features.
Or bits that you have to work around to get the job done.

12

It is only the few who have access to pay-for resources, but the open source community has already taken the lead in areas previously dominated by proprietary software, e.g. Apache, Linux, etc… I based my approach from the perspective of capability. I soon discovered that the free version of SketchUp didn’t have the capabilities I needed, and I wasn’t confident that the paid-for version would have either. In the end, I settled for using Excel formulas with a few macros to generate the lists of numbers that I need to produce g-code. Excel’s scatter graph tool provides 2D representations of columns of coordinates inside Excel, but I also use the Camotics (aka openSCAM) g-code simulator, http://camotics.org/, to see the result in 3D by reading the actual g-code that I’d be running to produce the object. I’d be the first to admit that my method becomes cumbersome with intricate objects, though the object pictured would only be quite onerous to achieve.

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I’m mac based and got TurboCad 2D many moons ago cause it was about the cheapest around at the time. I recently upgraded to 3D using an older version. It’s got all the bells and whistles and when I registered it I was offered a £50 upgade to the latest version worth a few hundred quid. I didn’t bother with the upgrade as my machines a bit older anyway and this version will save to files for 3D printers. Here’s what I got and it’s very good value.

http://www.ebay.co.uk/itm/TURBOCAD-4-FOR-MAC-PROFESSIONAL-VERSION-2D-3D-NEW-UK-/150645250693?hash=item2313281a85