Scanning half-hull models and developing plans

[US-SteamNavy]

BACKGROUND

 

I became interested in scanning half-hull models as an aside from my research on a particular ship, SS Meteor (1864).

I have a long-standing interest in the fast screw cruisers of the 1860s, including the Delano/Isherwood and Lenthall/Isherwood designs, and the privately-designed competitors: the USS Idaho by Steers/Dickerson, and Dennison Lawlor's SS Meteor. My interest also extends to British and French commerce-raiding and pursuit cruisers of that era: HMS Inconstant and related classes, and the four French-built Confederate raiders that became BAP América, BAP Unión, SMS Augusta, and SMS Victoria.  I recently obtained a scan of the HMS Inconstant plan from The National Maritime Museum.

The screw clipper Meteor (1864) was a smaller version of USS Idaho, but she had Scotish engines that delivered her promised speed. She was built by a Boston consortium to pursue Confederate commerce raiders, but was delivered too late for that purpose. The ship's trials showed her to be the fastest screw steamer in America, until the Navy tested its Isherwood-engined cruisers two years later. Despite attempts to use her in a commercial venture, the ship was really only suitable as a commerce raider, or for pursuing them.

 

RESULTS OF TESTING THE TWO GENERATIONS OF SENSE HAND-HELD SCANNERS

 

I have recently been successful in scanning a private half-hull of the USS Wampanoag, and the model of SS Meteor at the Portsmouth (NH) Athenaeum.  In late September I will scan the larger Meteor model at the Smithsonian Institution.  From these scans I will prepare traditional body, half-breadth, and sheer plans using SolidWorks.  Below are my recommendations for anyone seeking to use a Sense scanner to scan half-hull models.

 

TECH MEMO:

 

To Recap: For best results in scanning half-hulls, I have settled upon the generation 1 Sense3D scanner, paired with a Surface Pro 2 tablet (with the faster i5-4300U processor, and 4 to 8 GB RAM) running Windows 8.1. Both these devices can now only be obtained used or refurbished, and often the Pro 2 requires an operating system reset to Win8.1 from Win10.  However, the gen1 scanner has 3x3x3 meter capability and full user control of settings, vs. 2x2x2 meters and a too-friendly (impaired) interface with the generation 2 Sense2 scanner (retail: $360-400).  Out of the box, you can distinguish the two generations of scanner thus: The second generation "Sense2" has and "Intel inside" logo on the base label; the original (prefered) "Sense3D" does not.

 

The good news is that Cubify has become part of 3DSystems, and the formerly non-existent support for the Sense scanner has been replaced by exemplary 24-hour support. Software for both generations of Sense scanners (as well as the Apple variant) is found at:

Www.3dsystems.com/shop/support/sense/videos 

[Apple users -- note that at $80 the retail price for the scanner for your OS is roughly 20 percent the cost of the Windows scanner. Go figure...]

 

The older (gen1) scanner can be found for $200-350 on ebay -- usually in new condition, due to an initial frustration effect.  The Surface Pro 2 with 4300U quad processor has a nominal speed of 1.9 GHz, but ranges up to 2.6 or 2.9 GHz. That is plenty to drive the scanner, which the box says requires 2 GHz and 4 GB. 

 

I CANNOT RECOMMEND the 4200U SP2 (1.6 GHz and up), so shop carefully.  Expect to pay $300-350 for a 4300U SP2 on ebay (you may get a stylus included), or just go to Newegg and spend $330:

https://www.neweggbusiness.com/product/product.aspx?item=9b-34-735-142

 

In either case, you will need a $35-50 Surface Pro 2 stylus, because the sensor software is MUCH easier to use with one. 

 

A mount to join the SP2 and scanner can be 3D-printed from the design at:

http://www.thingiverse.com/thing:237449

OR you can contact me for my redesign of that mount (as a print file, or an actual mount).

 

 

Edited September 9, 2016 by US-SteamNavy

[US-SteamNavy]

 

When taking 3D scans, I have found a free online viewer (http://www.viewstl.com/) to provide a quick and easily manipulated rendering of the stl-format scan file.  You must have an active internet connection to use this viewer. 

Edited September 9, 2016 by US-SteamNavy

[US-SteamNavy]

 

To help the scanner maintain tracking when scanning a large smooth surface (a half-hull over three feet, for example), I distribute little traffic cones at 1- to 2-foot intervals around the target object.  If you lose tracking and imperfectly regain it, the active color image will show double cone tops -- you need to redo that scan.

Edited September 9, 2016 by US-SteamNavy

[druxey]

Would running the scanner along some sort of track/gantry near the object being scanned and parallel to its long axis improve tracking?

[US-SteamNavy]

On 9/16/2016 at 6:01 AM, druxey said:

Would running the scanner along some sort of track/gantry near the object being scanned and parallel to its long axis improve tracking?

So sorry to take six months to get back to this, but I missed it while I was on my 70-day road tour of maritime museums and Civil war battlefields.  (Along the way I demonstrated the scanner set, in addition to Portsmouth (NH) Athenaeum, to model shops at Annapolis, the USN Carderock lab, the Smithsonian, Mystic Seaport, and Philadelphia's Independence Seaport Museum.  I also viewed the half-hull and model collections at those museums and at MIT.)

 

To answer your question, I tried mounting the scanner on a tripod dolly back in 2014 at Mare island Museum. It did not give better results than the handheld method.  However, I was generally not successful then because I was using an underpowered (slow chip) laptop to drive the scanner.  Since that time I have not tried a track or tripod, so you may very well be right!

 

Use of the half-hull scans for taking of lines is pending, while I try out various software for rotating them and registering them to and x-y-z coordinate system.  At this point, my recommendation for this pre-processing of the 3D scans is the freeware Meshmixer.  I will post more later, with examples.

[druxey]

Thanks so much for your rather delayed reply! Look forward to your further experimental results. Hope it was a good trip for you.

[US-SteamNavy]

This project has been on hold for the past 14 months, while I was caught up in a family housing project. I have hopes of resuming training on and use of Meshmixer very soon. 

[wefalck]

Just as a sideline: have you been able to collect any information on SMS AUGUSTA and SMS VICTORIA ?

[US-SteamNavy]

I found write-ups on both ships in the attached sources.  If you do not have those several pages, contact me by email at craigecrouch@gmail.com; I cannot post them here because of copyright. 

[wefalck]

Thanks, I do have indeed these books. Photographs are rather rare and I wondered, what you might have been able to identify. At some stage I should check out potential French sources for drawings.