USS Tecumseh - Canonicus Class ACW Monitor

[DrPR]

Thanks for the offer. I might just install Blender and do some experimentation myself.

DXFs have always been problematic. The original definition was written by functional illiterates and is so ambiguous that no two people interpret it the same. I have known several programmers who have written DXF file translators and none of them came up with fully compatible programs. Also, because DXF is an ASCII text file format the files are huge. The binary file for the superstructure is 257 Mbytes. A DXF file would be about 1.5 Gigabytes.

I did a little experimentation this morning and the numbers I posted are wrong, or at least my interpretation of them. The superstructure has 440,000 "grid objects." These are not individual solids, they are the grid definition elements. I don't know how to translate these into individual solids, but I do know the polygon count is quite a bit larger than the grid element count. The drawing has about 79,000 entities (solids, planes, lines, etc.).

Phil

[tea monster]

...The original definition was written by functional illiterates and is so ambiguous that no two people interpret it the same...

LOL, when I was looking for an importer, people who'd written them said basically this, but they didn't directly say it, they just implied it in such a fashion that those words jumped into your head. Supposedly (I'm not a programmer), the format was originally for line drawings only, then got hacked by someone to contain a 3rd dimension. Lovely. I know a lot of 'Arch-Vis' artists use it to get house models out of CAD programs for rendering, so you won't be the first person to be looking for a pipeline.

I did a little experimentation this morning and the numbers I posted are wrong, or at least my interpretation of them. The superstructure has 440,000 "grid objects." These are not individual solids, they are the grid definition elements. I don't know how to translate these into individual solids, but I do know the polygon count is quite a bit larger than the grid element count. The drawing has about 79,000 entities (solids, planes, lines, etc.).

Phil

Dosen't sound too bad. You can put things on different layers and control their visibility. If you start experimenting and need a hand, just PM me.

[Roscoe]

...The original definition was written by functional illiterates and is so ambiguous that no two people interpret it the same...

Supposedly (I'm not a programmer), the format was originally for line drawings only, then got hacked by someone to contain a 3rd dimension. Lovely.

That's Autodesk for ya! (never did care for their software)

Owen,
looking better and better, by time your done it'll be one damn fine looking model.

Phil,
I just did a little test exporting a stl file from Solidworks into Blender 2.59, and it came out real well, no funky, mismatched surfaces or missing parts at all. You said your using DesignCad, and I know all exporters are not the same, but if DC exports that file type, it may be worth trying.
I would show you a screenshot, but I don't like posting pics like that in others threads.

Regards,
Dean

[tea monster]

I honestly don't mind. If you still don't want to, you can start another thread and we can trade info and render tips and stuff if you like.

[Roscoe]

I honestly don't mind. If you still don't want to, you can start another thread and we can trade info and render tips and stuff if you like.

That separate thread idea sounds good, somewhere to share ideas, techniques, whatever. Maybe you could show us Blender newbies some tricks of the trade, and although I'm no expert, I'd be happy to share some Solidworks stuff to anyone who's interested.

Would anyone else like to chime in?

Cheers,
Dean

[DrPR]

It's a good idea. We have hijacked tea monster's thread. He has demonstrated that Blender is a good tool, and it is freeware, so a Blender thread might encourage new users.

Dean,

DesignCAD doesn't export STLs, but I have used AccuTrans ($25) to convert DesignCAD DXF output into STL files, and it works nicely. That may be a very good way to transfer designs from CAD programs into Blender.

Tea monster,

Does Blender have dimensioning capability, or the ability to export 2D drawings? I know it is a bit archaic, but most modelers would prefer a dimensioned 2D drawing for creating models, even if just a PDF file.

Phil

[tea monster]

I've heard that the freebie QCAD will do the job, but I've not tried it out myself to actually confirm this.
Blender can sort of output 2D drawings, but you have to fiddle with settings a bit to do it. There is a 'toon' shader that you can use and there is an integration with another 'toon' shader called freestyle that is in a branch that you can use. I couldn't tell you the settings off the top of my head though (edit -link).

There is a 'caliper' plug-in and people have used it for some limited CAD work, but from everything I've seen and heard, you are better using something dedicated for designing and use Blender for the rendering and animating.

Yeah, I'm in on a thread like that. Would it be in this section or another?

[Roscoe]

Sorry for the hijack Owen, I've started another thread and look forward to hearing from you there also.

Cheers,
Dean

[tea monster]

No problems at all. I've already left a comment. I'll work up a 'quick and dirty' rendering pipeline post for tomorrow.

Got some more work done today. I found a sheet on the Yahoo ironclads mailing list and changed the colours accordingly. Finished up a lot of detail work. The only thing really left is the rigging, anchor chains and the railings.

Then it's on to 'proper' texturing and then some waterline renders.

[mcg]

It's turning out beautifully.

You may already have these -- a couple of archived photos of the "nostrils" on the USS Ajax, a re-named Canonicus class monitor that survived into the Spanish American war era. Not sure whether this massive anchor hardware was original or retrofitted, but anyway, worth a glance.

http://www.navsource.org/archives/01/ajax1b.jpg

One of these images was used on the cover of the warship Profile #36 on ironclads.

http://www.navsource.org/archives/01/ajax1c.jpg

It may be necessary to paint the link and copy it into the location bar.

Michael

[tea monster]

Thanks, I've seen them before, but you've posted it at a good time, as I was just looking for details on how the different flag poles and rail stanchions were attached.

Of the two big chain ports on the front, the huge one is a post-war addition. the second, smaller one is the original article. Since the war, she's received a nice wooden deck with a metal surround and vent/ stack caps - though the stack and vent look like original issue at first glance. The thing that gets me is that there is no visible plate detail on the side of the vessel. All contemporary artwork shows off huge rivets, but nothing is visible at all in that pic.



You can see the deck plates on this shot of the Mahopac, including the inset rivets/bolts. I'm even considering removing the current silghtly raised vent covers on the current model and replacing them with these flush vents as a bump map.

[Timmy C]

Navsource does not allow you to use the [img] tags to make them show up automatically - if you can see them, that's because your browser is loading the image from its cache. Other users who have not seen the image already will only see the broken image symbol.

[mcg]

Those cast circular grills may be deck-mounted skylight covers?

[Roscoe]

Those cast circular grills may be deck-mounted skylight covers?

Yeah, your right Michael, from everything I've read they were glass deck lights, (skylights) with metal (iron) covers to cap them when in combat. Really hard to find any good info on those, like most Ironclad details.

Owen,
looking fantastic, I love all those details.

Cheers,
Dean

[mcg]

They must have had kerosene lamps belowdecks. Might look cool at dusk, with all those underlighted deck lights, unless they closed them off as a security measure.

[Devin]

You should have to different sized circular deck penetrations. The smaller ones are indeed deadlights, which had thick glass inserts and could be plated over as you stated. The other, larger ones, are coaling scuttles. I don't have any positions marked out for them on the Canonicus class, but on the Passaics they were directly over the coal bunkers (makes sense) aft of the turret and forward of the engine room.

I agree that the hull looks odd. They must have plated it over. Or maybe Ajax was built that way. The raised carriage bolts that protruded from the hull and the turret on the Passaic class started to disappear on the Canonicus class (think more of a "flush rivet" look). The Camanche, a Passaic built on the west coast, had this feature too. Maybe Ajax was built late enough in the war that they took that feature to the hull sides as well.

[tea monster]

Timmy C - thanks for the heads-up. I've photo-bucketed my images from now on.

I've got a comparison between two of the different ships of the Canonicus class. I've been modelling my ship like the Saugus. On the Saugus, the vents are huge pot-holes with giant metal sink-stopper plugs that get pulled up and rest on the deck. On the Mahopac, they are more shallow, like shower-drains with some kind of rotating blocker plate. Now the Saugus was constructed in Delaware, while the Mahopac was built in New Jersey. Would this result in the differences? The bolts on the turret of the Saugus look more proud that those of the Mahopac as well.

The Tecumseh was built in New Jersey as well. Also, I've checked through the refs I've got and they actually did recover one of the vents of the Tecumseh! I've got a pic here:

Devin - I've got a deck plan arrangement done by Capt. Peterkin (who did an exhaustive examination of the Tecumseh when they were thinking of raising her in the late '60s) that shows a lot of the different deck vents and ports. It dosen't label them, but there are different sized ones and I've followed the shape and sizes of them - in the last pic I posted, you can see one of the larger disks in front of the smoke stack. There is a large rectangular access hatch over the engine room which may be the coal hatch. It could also be for transporting large engine parts into and out of the ship for repairs.

I'm thinking that you are right on the construction side of things. The two different monitors, of the same class, built on the East Coast have a different features and the West Coast one would be similar. I am thinking though that the wooden deck was added post-war.

So, to cut to the chase, I'm going to remove the small vent covers and add them in as bump maps on the texturing phase. I could cut them in, but looking at the scale of the things, a bump map would do the job more cleanly.

mcg - Yes it would, especially if they were reflecting off those canvas deck shades they used.

Roscoe - Yep, that was it. Thankfully, I'm finding that thanks to Capt. Peterkin and the efforts of the Smithsonian, there is actually quite a bit of info on the Tecumseh!

[Devin]

Wow, that's a great find. I've never seen that photo of the cover before. I wonder what else they brought up?

I'd say that the ships being built in different yards is most likely the cause for the differences. You see that even in modern Navy boats. Consider the fact that these ships were the first steel ship "classes" to be produced in multiple U.S. yards, yards that were building steel hulled ships for the first time, and you can see how there would be major differences. A good book on that topic is "Civil War Ironclads", it talks about the Canonicus class design and building issues, and the Casco class debacle.

Wooden decks are definitely post-war. The only Atlantic coastal ironclads I can think of that had wooden decks were New Ironsides and maybe Galena.

[Roscoe]

Those are some great pics, it would be nice if there was more like those on all of the Ironclads.

Dean

[mcg]

Still not quite understanding this hardware.

I am going to use the term skylight because it is intuitive and because �deadlight� turns out to have several different meanings.

The question is, are these devices ventilators? Or are they light shutters mounted over sealed skylights?

If they are adjustable ventilators, mounted over vertical holes penetrating all the way through the deck, can they be made 100% watertight when fully closed? The monitors� decks were often underwater.

Maybe the devices are instead intended to be light shutters over the skylights.

In battle or at night (for stealth, so that the deck doesn�t light up like a Christmas tree) you could close the shutters over the sealed skylights. I am guessing the shutters would be closed from above, from on deck. The monitors were vulnerable to boarding parties, and uneasy about it. Hence those deck cannons.

When you want both ventilation and daylight, you could pull the whole sink stopper, including the shutter and the skylight glass, and set it aside, as perhaps depicted in the Saugus photo.

Is the air register the divers recovered identified as a deck ventilator? In other words, is it the same hardware we are seeing on the photos of the decks? I guess that�s the most likely thing, but could it have come from below? Is the wreck upside down or right side up?

Puzzling. Another, uncomplicated possibility is that the skylights were covered with a simple fixed grill.

Michael