CN 'Porkchop' cab- taking the 3D design and printing plunge

[Scottl]

Notwithstanding some challenges about the quality of available retail 3D printing for n-scale, I decided some time ago that I wanted to take the plunge and try it from a design to final product.  This thread will take me through the process and hopefully give a venue for constructive criticism.  I'm new to 3D design, so it will be a learning curve.  If this becomes a reality, I'll be happy to share the design.

I'm going to build the iconic (well, iconic if you care about CN  ) cab with the drop windows (or porkchops) for the Dash 9 and ES44DC series.  CN runs a lot of these locomotives and this is the remaining gap in the n-scale modern diesel fleet, thanks to the efforts of Kaslo and FVM. 

Here are some examples for those of you interested:

http://www.railpictures.net/viewphoto.php?id=459434

http://www.railpictures.net/viewphoto.php?id=459455

I spent some time with Sketchup a while back and gave up- just not my cup of tea.   A link I found on Trainboard led me to https://tinkercad.com, one of the many emergent 3D packages available online for free.  I found it quite intuitive to use and the limited command set made the process very fast to learn.

Here is my first crack at the design, completely without proper dimensions.  It kind of looks more like a SD70, but my goal was to experiment with shapes to see what was possible, how to develop drawing standards, and to test making a hollow model.  After about 1 hour this morning with a few cups of coffee, I came up with this, which vaguely resembles my end goal.  Making it hollow was pretty simple but it is not obvious from this image that I have done that:



I'm also trying to work through some of the other issues to make this the best final product I can.  The hatches below the cab windows won't need to be done, as I can retain these from the Kato model that I will mount this too. 

I am envisioning adding the front door as a separate part so I can keep the main faces smooth for touch up.  I might even have a few doors left over from Kaslo kits, but I could etch it if needed.  Similarly, I'll etch side window frames to mount on the surface.

The number boards are probably best incorporated into the design.  I plan to have dimples in the faces for drill guides

We'll see how this goes.  I could sure use some dimensions to work from- any ideas for sources of these?  I can pull them from photographs, but that is not ideal.  Also, is anyone aware if the two models have identical cabs?  I have always thought that this was the case (less some details like the lighting), but I can't be sure.  Ideally, I'll make three versions:  Dash 9, and ES44DC with and without the red rear lights in the nose.

We'll see how it goes, comments and suggestions welcome.

[craigolio1]

This is great.  I'm looking forward to watching your progress.  I've wanted to experiment as well but like you, have no experience.  I'll take a look at that software link.

Thanks.

Craig

[Scottl]

Another hour of work and it actually looks like a GE unit.  The dimensions are pure eye-ball for now 



I'm still testing how to make things work, but it seems to be possible. 

[Ian MacMillan]

Very nice work so far. I too have been wanting to get started in this so I could bang out some MOW machines and.different models of speeders.

[TiVoPrince]

Once
again giving me hope for this:
http://espee.railfan.net/nonindex/tebu_photos/1602a_sp-tebu-bruce_morden.jpg
Someday, someday a TEBU bracketed by sound equipped GP40-2s screaming across the layout at 20ish miles an hour.

Cruel fate and a lack of talent in 3D design has prevented me from completing anything so far.  Difficult to have so much desire, but absolutely no ability or skill to move forward in a useful way...

[Scottl]

Well, I have four hours of 3D design experience, two on Sketchup which made no sense to me.  A new design program changed everything.

[Kisatchie]

Cruel fate and a lack of talent in 3D design has prevented me from completing anything so far.  Difficult to have so much desire, but absolutely no ability or skill to move forward in a useful way...

Man, ain't that the truth!


Hmm... make sure Kiz is
under oath when he says
that...

[TiVoPrince]

REV2
gets me thinking about this:
http://espee.railfan.net/nonindex/mk_photos/0503b_sp_mk5000c-stan_rothwell.jpg
Another of my ESPEE pipe dreams...

[Hedley Lamarr] My mind is aglow with whirling, transient nodes of thought careening through a cosmic vapor of invention[/Hedley Lamarr)... [/color]

[3rdboxcar]

Good start, unfortunately I do not know about tinkercad but I think you may find some problems hollowing out the shell, wall thickness is critical for 3D printing.

I struggled with sketchup at first but 1 year on feel quite proficient, my first printed part was PRR / CR cab signal box not as ambitious as starting with a cab straight away, overcoming some issues with compound curves etc. took me weeks to sort but once learnt it is easy now. The hardest part is getting accurate drawings.

Look forward to your progress.

Alexander

[Scottl]

I'm pretty sure Tinkercad would be difficult to use for a complex project.  Compound curves would probably not be possible, and filleting corners is a pain.  I have had some success hollowing out the model to 1 and 1.5 mm wall thickness, but I'm not going to go much further at it until I get some critical measurements from a Kato locomotive.  I might get a print of it to see how it looks before finalizing.

I enjoy doing this kind of work, so it might be worth revisiting Sketchup or learning something more sophisticated.  3D priinting will only get better and probably go fully mainstream, so this will be a great part of the hobby to be functional with.  What is nice for me is I can do this while travelling.

[ljudice]

Very nice work so far. I too have been wanting to get started in this so I could bang out some MOW machines and.different models of speeders.

Did you ever get that giant Plasser machine from the guy in the UK?

[3rdboxcar]

Hi Scott

I worked through all the sketchup tutorials http://www.youtube.com/watch?v=dL01iW9DAEUon you tube and bought the idiots guide which I still refer to.

I am still using sketchup 8, the new versions are a bit more towards you spending money, when you download sketchup make it automatically gives you the pro version which runs out after so many days, I think you can do less with the new "make" version than version 8. The license for "make" states you cannot use the software for financial gain, so in theory you could not sell your models on Shapeways.

Blender is the other software I had on my list when I chose sketchup.

Alexander

[Scottl]

Hi Alexander,

Thanks for the advice.  I downloaded and worked a bit with the Make version and I see what you mean.  Blender was something I had forgotten about, but I'll look at it when I get a chance.

Some more progress, refining the angles and the dimensions, and adding some details and the drill dimples.  The windows are placeholders for the final render.



I ordered a version of this through Shapeways today. It will be helpful to see what it looks like as I refine this.  It will ultimately be available to the public if it works out. 

http://www.shapeways.com/model/1518580/cn-canadian-cab.html

My print was less than $6, and it is oversized right now.  This is promising and a lot of fun!

[HuskerN]

scottl,

I took a look at your 3d rendering on Shapeways, and it appears that you have some design flaws in the numberboard and headlight areas.  It may appear ok in our drawing tool, but perhaps the upload process is distorting the file?  I have found that using a program like netfabb to clean up a file after sketchup and before shapeways, will ensure you have a "watertight" model suitable for printing.

I have only been using sketchup for less than 1 year now, but am getting much more proficient in my designs.  Keep with it, and you will also conquer the learning curve.  You are smart to begin with very square and boxy designs rather than something with a complex curve.

it has taken me this entire calendar year to feel like I really understand how to design a model for both 3d printing, and 1:160 scale.  There has certainly been some challenges, and trial and error to get it right.

here is my livestock trailer when it was progressing as a 3d drawing using sketchup.  This was a straight forward, and square cornered model, which helped me build my confidence.





HuskerN
www.nscaleaddiction.blogspot.com
www.shapeways.com/shops/NScaleAddict

[Scottl]

Thanks Husker,

I saw that error too, but could not figure out how to make it go away initially.  I thought that testing for a print would be worthwhile, as a learning experience at the very least.  I subsequently rebuilt the number board and the problem went away, but I would not be surprised if I have more issues.  I'm not too fussed about a few botched prints due to design issues- the cost is low enough.

Netfabb looks very helpful- probably beyond my means for this type of work, but perhaps I might develop a habit with this type of work and could justify it.  Reading their tutorials is an eyeopener- there is a lot more to this than meets the eye!  I appreciate your input and encouragement.

Cheers