Reverse engineering scale models

Great ideas, but the process is really simple form the suggestions already given.

Just use the profiling tool to do sections along the length, type the co-ordinates into a text file, and use Freeship or Delftship to generate the hull form. This will do away with perspective and lighting issues, which is way overkill for this little job.

It will also then provide you with all the hydro info like displacement, COG, etc etc.


http://www.boatdesign.net/forums/design-software/delftship-chine-import-34688.html for some hints

 

I haven't used that method but it's been done. Set up is per post #14, i.e., camera normal to light sheet. Verifying per Earl's suggestion using card forms is a good idea too.

 

Many thanks for the link. It's a very interesting book.

 

I do heartily agree.

 

I once shaped a half hull using 3":1' scale. After tracing the profile I glued the model to a piece of 1/2" x 6" board with the waterline parallel to the edge of the board. Next I cross cut it every 3" on the sliding compound miter saw, the equivalent of every 1' on the full size hull, and traced the sections. From there it was easy to draw in waterlines and take the half breadths.

 

as it's a small model, a quick method is desired, as well as a CAD result - so how about loading up the CAD program, setting it to draw a continuous line, setting the model up vertically beside the cpu mouse and taping the mouse to an old fashioned T-square, drafting arm, drafting machine or parallel rule that has a temporary pointer extension tacked on that touches the model at a point. (the key is that 'arms' of these typically are set to always keep the same orientation)

Assuming the model has tick marks at all stations desired, just move it vertically up or down to the next station coplanar with the mouse surface and drag the pointer (which has the mouse attached, heh heh) across the surface station/section of the model.

One would choose the appropriate zoom factor and not change it thruout the procedure, but it just might be ok. The key would to be able to move the model up and down fairly accurately - simplest would be to attach it to a base that could clamp to the desired vertical.

As one would have to rescale anyway, the sections are just as useful as if they were at some original input scale.

Quick, cheap, and no measuring required. Might work, too.

 

Great idea

Cut up the master hull for sections when you can just take the profile of the hull at the stations with the profile template thingy ?

Yeah - maybe some designs deserve to be cut up.