Cost of Digitising Plans

[Eric Sponberg]

Originally Posted by Mat-C

Thanks Eric,
"Digitising" was probably the wrong word to use. What I meant was to take a set of (hand drawn) lines &/or offsets and turn them into a 3D model (Rhino I guess?) and then make a cutting file for mold frames etc.....

That's more expensive to make the 3D model, and there will be some slight inaccuracies in the translation. The fairing process is not automatic--the designer will first have to trace over your lines plan into AutoCad to make a .dxf copy of your linework, and then import the .dxf line patterns into the surface modeling program. Then he'll decide on the number of surfaces to create, and then fair those surfaces into place such that the new lines on the surfaces will be as near duplicate to your original lines. But they won't be perfect. The more highly skilled the designer, the more accurate the result will be. It is all trial and error, and it takes a while--hence the higher cost because of the extra design time. You should try consulting a few different designers with a picture of the boat and have them quote on it. You'll get a variety of answers, and in the process you will likely find the one you can afford and deal with the best.

If your lines are well drawn, it might be sufficient to just go as far as the AutoCad version of the lines, and take the patterns from those. If they are accurate in your drawing, they will be just about as accurate in AutoCad. It is in the surface modeling that you will lose some definition, and so maybe you don't need to go there.

Of course, we haven't seen your lines so we cannot comment much further. Each boat is different, and that is probably why you should get a selection of quotes. You are going to spend at least a few thousand dollars anyway for a surface model and patterns.

Eric

[DCockey]

Any reason not to start with offsets when they are available, and enter them directly into Rhino or other software capable of modeling 3D surfaces accurately? Then model build the 3D model of the surface starting with the points from the offsets (which is not trivial). Depending on how complete the offsets are, and the spacing between the various sections, waterlines, buttocks more information many be needed from the lines, similar to what's needed in lofting.

I've been busy creating 3d surfaces from a number of designs, and if the lines and offsets are good and the surface is feasible I can usually get a fair surface within the accuracy of the offsets. Good lines and offsets require fair curves which properly intersect, and then the offsets have to be lifted accurately.

Anytime a set of lines is translated into a 3D surface, whether it be virtually or by building a boat, there is the opportunity for discrepencies to arise.