Computer Aided Drafting

Dave Stevens (Lumberyard)

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I also like to use polyline because you can edit and join them and create an object

the top section coming off the flat center line is made up of 3 joined arcs end to end.
 

Dave Stevens (Lumberyard)

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here are samples of what to expect going from images of drawings and actual CAD drawings

if the drawing was leveled the lowest red line is level but look at the 2 lines above it they are also level with the lower line but off to the drawing and the top line green arrow runs off in the other direction

frame 2.JPG

when working in CAD you set a center line the light blue line and a base line to work off of. The left side is a tracing of the plan but when you mirror the left side to the right using the center line your way off.


column base t.JPG

STL 3d print files will be made from the original CAD drawings. if I were to actually have traced the original none of the parts would fit and the entire engine would be totally cattywompas.

i have been working on these CAD engine drawings for over a year so expect to spend a lot of time in front of your computer. The sheer amount to corrections from original to final CAD drawing will keep you busy for a long time.

frame size.JPG

many model builders said "boy i would love to pick out a ship, draw modeling plans, make part patterns from the drawings and build a scratch model."

it can be done and is done all the time by people who know CAD inside and out and have a firm grip on creating 3d modeling, and a bend toward model engineering.

in the days of old ships were really not built from plans they were built by the numbers in what was called a table of offsets. So the old plans you see are not working plans at all. Building a ship from plans is a model ship building thing.
 
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davef

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To add to Dave's comments.
The master shipwright also made changes to the ship as he built it. Personal choices or what would work as they built it.
Remember wood is not a constant medium so some times they had to make changes.
Your plans or anyone else's are your interpretation of the ship. It's not wrong but it's also may not be what was built.
Dave F
 

Dave Stevens (Lumberyard)

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while on the subject one thing became clear to me as I drew the steam engine. I know CAD pretty good and have no problem in drawing the parts in both 2D and 3D.
What became a problem was the fact I do not know how a steam engine actually works and what all the parts are and how it all fits together. So I have part A that fits into part B which bolts to part C and part C has to line up with parts D,E and F. I have no clue if parts are missing or not or what they even look like.
Take a ship there are hundreds of parts that all fit together. If you do not know how a ship is built and all the parts that go into one you can not draw it.
there is a keel, keelson, rising wood, deadwood, apron floors, riders, sister keelson, stem, inner and outer stern post. As you work your way up the hull there are futtocks, clamps, counter, transom and so on.

There are few stand along parts each and every piece depends on another.

not to sound like I am discouraging anyone from trying this. As it is we have very few people who can start from scratch and come up with a set of working modeling plans.


Dave F also makes a good point

a master shipwright draws a plan and note there are no parts in these plans just an overview of a ship it is up to the yard foreman to "build" it. He may take an inventory of timbers in the yard and decide how to frame the hull.
in model ship building we would tend to keep everything even a 5mm thick frame and a 3mm space another 5mm frame and another 3mm space. Real ships were build with random frames and spacing depending on timber in the yard and the shifting of timbers to accommodate different features of the ship. different countries built different ways, shipwrights built different from on another. Before you draw the first line you need an understanding of what you drawing.
 

Dave Stevens (Lumberyard)

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CAD drafting and 3D modeling and 3D printing is indeed the future wave of this and other hobbies. What better set of instructions than a 3d model you can view at any angle and details down to the actual nuts and bolts. You can see examples of this in the works on this forum.
I encourage model builders to take a look at CAD drawing. Yes it is a steep learning curve but once you got the basics your on your way.

as I engineer the steam engine I ran into a question what is the "gland" on the side of the condenser, ( the blue thing) Rather than try to explain what I want all I have to do is go to the 3D model zoom into the location and BAM! there it is. a big pipe type of connection. The person I asked instantly recognized it. So a 3D model is worth a 1,000 words.

capa6.jpg

we have to rethink the old ways. There are model ship builders out there who snub 3d printed figureheads and carvings because they are not hand carved from wood and they cry "I would never use plastic on a wood model". The idea is to re engineer and re produce a ship the way it might of looked like. So what if the carvings are cast resin or 3d printed or carved from wood it is the final result that counts.
Some even said that is cheating and not a crafted model. CHEATING! really sit down and try to create a STL print file, you may spend more time and skill trying to produce the final results by printing it.
 

donfarr

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BEEN SAYING THAT FOR QUITE A FEW YEARS, I DO NOT UNDERSTAND CAD or 3-D MODELING BUT I SURE AS HECK KNOW THAT IT HELPS ME GREATLY AS AN INTERMEDIATE MODELER. AT MY AGE LEARNING CAD 3-D MODELING IS JUST TO MUCH, BUT AS YOU SAID DAVE IT IS THE END RESULT THAT COUNTS. THANK YOU AGAIN FOR ADVOCATING THE FUTER OF THIS GREAT HOBBY. Don
 

Grandpa

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I had run across a few threads back when I was active. This was maybe 3 years ago. I tried using the search feature at the top of this site, but CAD is too short and Computer Aided Drafting failed to produce any results for me. Do any of you have links to using CAD to work with existing plans or to create plans for model ship building? I have a student copy of Autocad 2020 for my online class I am currently taking and trying to relearn the application. I used to use an older version of Autocad and also Bentley Microstation way back.
Thanks,

Jeff
Jeff I use AutoCadLt 2007 which is all I need for my use. Currently drawing a 1959 tugboat which was built at a welding firm near St.Catherines, Ontario, which since gone out of business. Just drawing it from various photographs. More drawing has been done since these photos were taken.0A768291-A58C-453C-94BB-BB9D668B6A5A.jpegF2E0B727-8AEC-4018-95EA-37A935DD918B.jpeg1039FCEC-CD32-4B39-9DAE-8CA9EDDAA484.jpeg181D54DC-8969-465E-B036-E7EF89DB532A.jpeg
 

danielsje

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Bob Hunt has a decent mini practicum for CAD on his site Lauck Street Shipyard...he is also an expert in CAD drawing of ship lines...send him an email and he will gladly answer...
 

JArthurD

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Not sure many CAD guys would share this opinion with me but I’ve used both and find Microstation to be friendlier. Both are very expensive. I guess it’s a matter of preference.
 
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