Hull fairing

Thank you for the comment and picture, this is what I been trying to do. Yes when I drew it up I new nothing else then 3d-polylines. I get what you are saying with less points, but what lines do you use to lay out the longitudes to connect the points. May I also ask what program you used?
I have gone back to start and are laying out 2 dimensional half breaths in Autocad and will concentrate on one half without deck to start with, then I have some time to decide on what program to use for laying out the hull.

Thank you all for your comments and help.

 

Here's a sample of what you can get with AutoCAD. I used splines instead of your polylines and, without changing a single point of your transversal sections, I've gotten the attached model. It seems that the hull model is smoothed than you thought.
Take my advice and do not change the software till to check, convincingly, that what you have does not serve you.

 

Wow, now I really get confused, is it that simple?

Cad is not my strongest side, I mostly work with my hands, but as I'm soon to retire I was thinking of doing this as a hobby in my years to come, and it's always good to learn something new, so one does not "fall to sleep to early".

My goal is to learn it the modern way with CAD and CNC-routing, just really for the challenge of it.

Would it be an step by step tutorial for going the Auto-cad way and then into solid-works for stringers, bulkheads and interior?

I played a little with splines and I think it will work, and yes you are right, I don't want to get to fare away from the original design.

Terje

 

In this forum, as elsewhere, everyone is happy with the software he uses. Therefore, you can have many opinions, all differing, on what software is the best. People will tell you what they would do, rather than say how you have to do what you want to do.
So again, my advice is to explore in depth the tool you have at hand, before changing to another.
The model of your boat is simple, if you do it simple.
Splines are good to create longitudinal curves. However, to define your cross sections are suitable polylines (splines would be a disaster).
That is, you should know what is the most appropriate tool for what you need to do. You will get that with practice and learning from mistakes.
Another thing: you can create drawing in AutoCAD, with parts of your hull nested in a cliché, that any numerical control machine is capable of processing and cutting. So you need not search for a special CNC software because you already have it.
Regarding the reinforcements with SW, I attached two pictures of what can be done with AutoCAD

 

Tansl just as a matter of interest what tool set does autocad have for checking the curvature and fairness of curves and surfaces?

 

I do not know exactly what you mean by "checking fairness". Fairing has always been a matter of good eye and skills of the artist. You can not translate it in practice, I repeat, in practice, to mathematical methods.
Attached pictures show tool palettes AutoCAD provides the user to work with surfaces or meshes.

 

Tansl sorry I’m not talking about the notion of “fair” in a curve, as you point out its a matter of opinion. In rhino as well I see in autocad you have surface analyse, Gaussian and the like to show deflections in a surface. In rhino and other software you also have a “line graph” which shows you the curvature in more detail than you can see, as an example in the two pic's one show a curved line in plan and profile say of a shear, all look 's ok but when you turn on the line graph you can see a hollow at the stern and the profile has a flat spot. By adjusting one control point out by 30mm and one down by 60mm I have improved the look of the curve.

 

bhnautika, I'm not a loftman and therefore I will not go into the intricacies of this work. I have seen many loftmen working on several shipyards (big and medium sized) and, of course, none used the tools we're talking about you and me.
In AutoCAD you also can watch the surface normal vectors, which gives you a very good idea on the degree of smoothness of the curve or surface and also act on these vectors, but, as I say, I have never needed, neither I nor my staff, use those things.

 

Tansl I'm interested in the “normal vectors” as a method for showing smoothing. Could you post a picture of the file in post 17 with them on, say on the first chine line, just down from the shear. Being a flat panel, getting good edges would be more important than surface smoothness.

 

Sorry but I have said something that is not true, or at least, I am not able to find at this time, the option to display normal to a curve or a surface. AutoCAD can give the direction cosines of normal at one point but vector is not displayed
It is a tool that I used at the time but it was probably with Inventor or Mechanical Desktop. Sorry my mistake.

 

Tansl no problem, I know its not part of you work flow to do this but I was interested in seeing the differences. I copied two chine lines across and turned on the curvature graphs. I then adjusted out the peaks and hollows on the copies, the max difference in old (white) and new (red) in plan was 7mm and in profile 25mm (in the bow area).

 

bhnautika, I do not quite understand what conclusion you want to reach but it seems that you show that the curvature is not uniform, which does not have to be bad. Am I wrong?.

 

Tansl you need tools within the software to analyse and magnify curvature to get a true smooth curve on a computer screen. A smooth curve with out waves and wobbles, hollows and humps has got to be better than something that wasn't intended.

 

bhnautika, yes, I totally agree with you, but let me copy what a great professional, TheLoftsman, a member of the forum, sais: "Fairline" A line That is pleasing to the eye!

 

Tansl If we look at the original post, temo said “*What I discovered was that the hull is not 100% fair along the chines. So I've been thinking if there may be a program that I can import the model in(either as dxf or iges) where I can do the fairing, and I also want to flatten some panels on the hull for CNC-cutting? I then want to take the model into SW to do the bulkheads and interior, all ready for CNC-cutting.” so talk of lofting is not relevant but getting smooth lines is for cnc, might just be important. You may also want to rethink your statement in post 7 “Fairing of shapes can be done with AutoCAD, Rhino can not. “. The offsets of the original model, by the look of it, were not 100% so sticking with them as they are and hoping to fix things later seems strange, considering temo wants to model everything off the model.