Newbie to 3D printing and cad

[Daveyg04]

Hi guys

Forgive me if this has already been talked about like 100 times but recently joined,i model in o gauge and have been fasinated by this 3D printing, im totally clueless regarding it but would love to get into it and eventually have a wagon printed out.

What are the first steps, download something like sketchup and play about with it?

As regards the design of something you would like to have made do you need sizes to hand or can you scale it through software?

Any help would be great

Thanks in advance

Dave

[backofanenvelope]

Dave,

 

Hello and welcome to the group. Time spent going through it will unearth loads of useful information and if you look at the stickies at the top of the group you will see lots of 3D software links. Sketchup is a great program to get started on and you may find that you move onto others. Yes playing around is good for learning and search youtube as there is a wealth of info and tutorials there. As for building things if you want anything near to scale you will need drawing or at least some dimensions. Depending on your intended build there is probably info out there As for building in 0 there are number of people doing it here and they will better be able to comment on this. But have fun thats the name of the game and ask questions and where 'we' can they will get answered.

[Rabs]

Welcome!

I agree with backofanenvelope - try reading this section and playing with the software you are likely to use.  Sketchup is good for several reasons:

It's easier to learn than most 3d drawing packages

There's tons of help out there and tutorials to read/watch

It's free

 

However, it does have it's limitations so, assuming that you do choose to use it, I recommend:

Step 1: Before trying to learn how to design for 3d printing just do some general 3d drawing in sketchup and learn how to use its tools. There is a bit of a jump from being able to draw an object and then being able to draw it in a way that a 3d printer will accept.  I think that you will probably want to learn how to draw and manipulate shapes in sketchup before adding in another layer of (3d printing specific) difficulty.  It's nothing to be scared of, but taking it one step at a time will help.

Step 2: Once you are comfortable with Sketchup, but before you launch into something complex like rolling stock to print, try designing something simple like a postbox or a barrel for printing and upload it to shapeways.  Their online model checking will help you to see how you need to adjust the way you draw objects to make it suitable for printing.  That way you won't waste time getting a design that looks perfect only to find out that it's not watertight or that it's got inverted faces (don't worry about what these are now, that can wait until you're past step 1)

Once you're happy with these then you'll be well set-up for doing something more complex for printing.

 

Good luck

[Marbelup]

One issue with regard to measurements and scaling is whether to do the 3D model in full size (1:1 scale) or the model scale.

 

Like many things, there are pros and cons. I have tried both and I prefer to work in the model scale (1:64 for me) as it is easier to keep tabs on design requirements like minimum wall thickness and minimum detail size, depending on your target 3D technology and material.

 

There is a third alternative which is to work in an an intermediate scale, e.g 10 x model scale, then scale down the resultant STL file for printing. I haven't used SketchUp myself, but I understand some users work in a larger scale as it doesn't handle small measurements precisely. I use Rhino 3D software which has a precision of 0.001 mm which is precise enough for the most detail model I can envisage.

 

Another useful software tool is NetFabb which checks and corrects minor errors in STL files. Use of NetFabb is a good precaution before uploading an STL to a print service bureau, as it virtually eliminates the chance of the file being rejected due to errors. NetFabb is available both as a free download or as a cloud service. I find the cloud service is better at checking and correcting errors, but I also use the PC version for viewing STL files and rotating them when I want to print in a specific orientation. The PC version is also good for scaling STL files, if needed. I recently scaled some parts done in S scale for printing at 10 mm scale (210%) for another modeller.

 

If you are just starting out with 3D design software, another potential package to try is Design Spark Mechanical - http://www.designspark.com/eng/knowledge-item/read-about-designspark-mechanical

This is available free to "engineers" and has a precision of at least 0.01 mm, so it should be suitable for designing in the final model scale. I haven't tried it myself so I can't vouch for its ability to handle complex designs but it sounds like it is in the same league as SketchUp.

 

In my opinion, it would be worth trying a couple of different 3D software packages with simple designs before committing to one or other. I tried 123D initially and found it quite difficult to do precise work (for example, there was no global coordinate system) then I trialled Rhino and made rapid progress.

[Rabs]

Good point.  Sketchup is a bit of an oddball becuase it's about the only bit of 3d software that cares what units you are using.  Most tools don't mind if you design is several kilometers long or just a few nanometers - it's just a number to it.  Unfortunately sketchup seems to have problems drawing radii less than about 1mm, for some crazy reason.

To avoid this I personally draw in 1000x the model scale when using sketchup with the units set to meters and I imagine a second 'm' on all the dimensions.

In most tools this nonsense isn't needed.

 

If you have the time then Marbelup's advice to try a few different tools is good.

 

In my more recent designs (on solidworks - a professional CAD package that I used for business) I have drawn the shell of the model (and other bits that I want to be to scale) in 1:1 and then scaled this down to 1:148 to add all the model-specific innardss.  If necessary I also adjust the dimensions of some of the scaled down bits to make them printable.