USS St Louis Free 3D design files From World of Warships

Hi

Thanks for the link.

Pat

Looks like fun, I'll check it out.  

That's pretty awesome! Now to get a 3D printer . . . 

So, what is an FDM printer?

Just an observation: unless my math is off, it looks like the scale is 1:162.5

That's a pretty big model: nearly 3 feet long!

Lufbery

So, what is an FDM printer?

Fused Deposition Modeler (see also FFF, Fused Filament Fabrication) printing uses an "element" (looks like a string) fed to a printer head which brings the filament to its "melting" temperature and lays that element down in a series of layers.

This is in contrast to STL, Stereo Lithography, where a laser or similar collemated light source is used to "fix" liquid resin into fused particles.  (This is similar to Laser Sintering, where flaked or granulated particles--e.g. "sinters"--are fused together by the laser into a whole.)

"Filament printers" are generally less expensive to purchase, but the material cost of the various kinds of filaments can be as daunting as buying ink for inkjext printers.  Their printing ability is based on the size of the printing plate, and the vertical rise of either the print head or the plate.

"Resin printers" tend to be a bit more expensive to start, and are limited by the size of "the tank" of liquid resin for x-y, and the stroke of the z axis on the printer.

The liquid resin printers typically have an order of magnitude more "fineness" in their prints, as that is controled by the diameter of the intersection of the collemated light beams, rather than a heated nozzle.

Both will have "layer grain" but to different degrees.

Cost of the liquid resin can be steep.  And it can have a limited shelf life, unlike FDM filament.  Also, liquid resin prints need to be washed (typically) after printing, and want a UV light bath in a "curing tank" after the washing.  This can represent a cost overhead beyond the printer (and the desktop footprint can vex, too).

A person can work the edges of the lower-cost options in all of these.  But, it winds up being a bit like getting an airbrush.  You can start out cheap, but wind up spending more for better equipment later.  The parallels of canned air, air tanks, compressor(s) are also apt.

Lufbery

...

Just an observation: unless my math is off, it looks like the scale is 1:162.5

That's a pretty big model: nearly 3 feet long! 

Hi,

I have the worst time with trying to figure out the scale used in some 3D models.  For this one, when I pull the whole hull section into either Meshmixer or Chitubox (which is a program that I use to prepare the model for printing) it shows that the whole hull has the following dimensions;

L - 517.36mm

B - 80.94 mm

D - 63.29 mm

Looking at Wikipedia for the C-20 USS St Louis it lists the following dimensions;

L (overall) - 426.5 ft or 130.0m

B - 66ft or 20m

D - not listed

As such a 130m long ship would be 130,000 mm long, and dividing the model length of 517.36mm by 130,000 mm gives me a scale of about 1/251 scale.  Doing the same for the beam gives 80.94mm/20,000mm or about 1/247.  As such, my estimation is the the model is probably about 1/250 scale, as the dimensions listed inWikipedia may be scantling dimesions, not including plating or any other minor protuberances, while the model is molded with things like fittings and armor plating sticking off the sides etc.

However, I am not sure whether the programs that I am using may have tried to internally convert the files from metric to imperial or something like that.  Out of curiousity how did you come up with your estimate of 1/162.5?

Regards

Pat

CapnMac82, thank you for the detailed reply! I did notice the layering is some of the build photos. 

PFJN2

 

However, I am not sure whether the programs that I am using may have tried to internally convert the files from metric to imperial or something like that.  Out of curiousity how did you come up with your estimate of 1/162.5?

Regards

Pat

 

Lufbery

I guess it would be possible to print at some smaller percentage of the full-sized plans to get to 1:350 scale (for example), but I wonder if there is a limit to how well the printers work at those smaller scales.

Lufbery

 

 

PFJN2

 

However, I am not sure whether the programs that I am using may have tried to internally convert the files from metric to imperial or something like that.  Out of curiousity how did you come up with your estimate of 1/162.5?

Regards

Pat

 

 

 

 

Hi Pat,

 

The download document shows the model as being 80cm long. I got the same overall length of 130 m that you did when I looked at Wikipedia for the real ship.

 

130m = 13,000cm

 

So, 13,000cm divided by 80cm = 162.5. One CM on the model represents 162.5 of the real ship.

 

Just to double check because math isn't my strong suit, I checked this site: Scale Calculator - Online Scale Converter

 

I got the same scale.

 

I guess it would be possible to print at some smaller percentage of the full-sized plans to get to 1:350 scale (for example), but I wonder if there is a limit to how well the printers work at those smaller scales.

 

Regards,

 

Hi,

Thanks for your response.  In looking closer at the files it looks like the full hull model and the individual pieces may not be to the same scale.  Specifically, as I noted in my previous post the full hull file shows up as 517.36mm, but when I pull up all the individual pieces I get;

Part A (The Bow)  - 176.79 mm

Part B (ForeDeck) - 176.80 mm

Part C (Midships)  - 148.80 mm

Part D (Aft Area)  - 162.72 mm

Part E (Stern)      - 162.67 mm

-----------------------------------

Total Length - 827.78 mm

Dividing this by 130,000 mm full scale length gives a scale of about 1/157.

Similarly taking the width of Part C of 129.51 mm and dividing by 66 ft (20,117 mm) for the full scale beam gives a scale of about 1/155.

Regards

Pat

JoeSMG

scale that can reliably print rails and other fine detail, at least with an inexpensive home FDM printer.

Note that most printers will require "supports" for things like rails, as you can't "print in air" reliably.  The printer will have a specification for its smallest extrusion.

I have found that you do not want to get too close to that minimum diminsion, as it can be hard to discern the difference between the meant part and its support.  Also, the print can get unpredictably fragile, too.  So, you have to be extra careful to not be too ham-fisted with the diagonal cutters freeing the part from the support.

There is a "dodge" in that you often can print rails and the like separately, rather than as part of the hull or larger part.

Many FDM printers--especially with economy models--will have, for lack of a betterword, "difficulties" rendering round objects parallel to the base plate.  It's very typical to cant objects in relation to the base plate, as this renders "round" better than "normal" to x/y/z.

That's from how a round surface presents to the printer.  A cylinder "normal" to the base plate will have one (typically) "bead" in contact.  The next "bead" is raised, infetesimally, on one or both sides of the first.  But, that next pass is very much in a molten state from how the printer is extruding the material.  But, without supports, the next pass is like to sag.  That persists until the top of the cylinder is printed.

So, what you get is an oval, and often an egg-shaped sort of oval, as the upper surface "prints" better than the bottom.  This can be worse as you close in on the minima for printing (finding your round railings looking rectangular is under-satisfying).

The tech is a marvel, without a doubt.  But, it's not a be-all-to-end-all.  There's going to be an excellent case for modelers to "model."  That PE and the like may still have a place in the 3d print world.

It's one of reasons I liked this St Louise model, the designer's boast of "no supports needed" agrees with my approach, you'll get better results when you part up the design for best printing without supports and then assemble it like a traditional model. It's a lot more work to design, print and assemble this way but final product quality definitely improves.

Again this is true for inexpensive home FDM printers. More expensive dual head printers have been around for a while, one head has the PLA or ABS filament used to print your model while the other head has a water soluble filament used for the supports. In theory this should allow you the dream of the one shot print and done without the normal problems of removing the support material. I'd love to see how this works in practice.

Youtube link to a (completed) work in progress video of this model by someone who knows what the're doing - Spoiler - it ain't me!

https://www.youtube.com/watch?v=SwYTyPFoBTc