computer lofting software

[hank woll]

hello-has anyone got the skinny on software for lofting?-i know it is available but where?-hank

[hank woll]

hello-has anyone got the skinny on software for lofting?-i know it is available but where?-hank

[gert]

I just used ACAD

[gert]

I just used ACAD

[Bruce Hooke]

I've used AutoCAD but I can't imagine how you could effectively use it to fair the lines, which should be part of the lofting process...

[Bruce Hooke]

I've used AutoCAD but I can't imagine how you could effectively use it to fair the lines, which should be part of the lofting process...

[Ken Hutchins]

Bruce, to fair a line zoom in on a suspect area, edit the spline, delete a point at the suspect area. If the spline moves it is not fair. create a new point on the new spline. A bad point on a spline will show a pronounced wave in the spline. after recreating the spline check it in 3 views. This process will work in most CAD systems so long as you are working in 3D, if you are working in 2D it can be done but you have to duplicate the effort for the other directions.

[Ken Hutchins]

Bruce, to fair a line zoom in on a suspect area, edit the spline, delete a point at the suspect area. If the spline moves it is not fair. create a new point on the new spline. A bad point on a spline will show a pronounced wave in the spline. after recreating the spline check it in 3 views. This process will work in most CAD systems so long as you are working in 3D, if you are working in 2D it can be done but you have to duplicate the effort for the other directions.

[AHall]

Ken: I am very interested in any information you can share regarding lofting with Autocad. I am a Autocad user, but all my work is done in 2d (utility work mostly)

What I would love to be able to do is take a plan that I have and calculate the hull volume below the waterline. If all goes according to plan, I will use this displacement for my engine/prop sizing.

If it matters, The boat is an Arno Day 28'x10'cedar on oak lobsterboat.

any suggestions would be great.

Thanks,
Andy Hall
Lynn,MA

[AHall]

Ken: I am very interested in any information you can share regarding lofting with Autocad. I am a Autocad user, but all my work is done in 2d (utility work mostly)

What I would love to be able to do is take a plan that I have and calculate the hull volume below the waterline. If all goes according to plan, I will use this displacement for my engine/prop sizing.

If it matters, The boat is an Arno Day 28'x10'cedar on oak lobsterboat.

any suggestions would be great.

Thanks,
Andy Hall
Lynn,MA

[Ken Hutchins]

Andy, what you need to do is find the area of each section, this can be done with TOOLS INQUIRY AREA then pic points around the area (hull shape). All points must be in sequence and the start point and the end point must be connected CR and the resulting area will be displayed. Do this for each section. The volume between 2 adjacent sections will be the average of the 2 values times the spacing. Now this might produce a slight error depending on the total hull shape but for all practical purposes the results will be just fine for what you want. If you have 3D available you can create a poly line of the hull shape, extrude the poly line to the section spacing and get the volume of the resulting soild with TOOLS INQUIRY MASS PROPERTIES, do that to 2 adjacent sections and then average the result.
Basically what you would be doing with CAD is what would be done with a planimeter in the days of old.

[Ken Hutchins]

Andy, what you need to do is find the area of each section, this can be done with TOOLS INQUIRY AREA then pic points around the area (hull shape). All points must be in sequence and the start point and the end point must be connected CR and the resulting area will be displayed. Do this for each section. The volume between 2 adjacent sections will be the average of the 2 values times the spacing. Now this might produce a slight error depending on the total hull shape but for all practical purposes the results will be just fine for what you want. If you have 3D available you can create a poly line of the hull shape, extrude the poly line to the section spacing and get the volume of the resulting soild with TOOLS INQUIRY MASS PROPERTIES, do that to 2 adjacent sections and then average the result.
Basically what you would be doing with CAD is what would be done with a planimeter in the days of old.

[AHall]

Sounds good Ken. I already have areas of all my sections using a planimeter. Now there is a piece of "voodo equipment" I traced each area a few times however, and got repeatable results. My hat is off to whomever invented that device.

I was hoping for an easy way to get a 3d model of the hull. (doesn't sound like it exists) Are there any shortcuts to get from feet,inches,eights on the plans into Autocad frendly units?

I will have to fool around with the spline commands and see where that gets me.

Thanks for your reply,
Andy Hall

[AHall]

Sounds good Ken. I already have areas of all my sections using a planimeter. Now there is a piece of "voodo equipment" I traced each area a few times however, and got repeatable results. My hat is off to whomever invented that device.

I was hoping for an easy way to get a 3d model of the hull. (doesn't sound like it exists) Are there any shortcuts to get from feet,inches,eights on the plans into Autocad frendly units?

I will have to fool around with the spline commands and see where that gets me.

Thanks for your reply,
Andy Hall

[Bruce Taylor]

was hoping for an easy way to get a 3d model of the hull.

FREE!ship is fairly easy to learn (free download at www.freeship.org). 3D models can be exported to CAD as 3D or 2D .dxf files (face or polylines).

[Bruce Taylor]

was hoping for an easy way to get a 3d model of the hull.

FREE!ship is fairly easy to learn (free download at www.freeship.org). 3D models can be exported to CAD as 3D or 2D .dxf files (face or polylines).

[gert]

actualy fairing lines on acad sucks.
I just drew all the stations out (on CNC) for Grey Seal full size on a sheet of black melamine (glue up table); there were 3 "bumps" on 3 stations.
I went back to my 19" monitor and they are not apparent.
Nothing a bendy stick won't fix [img]tongue.gif[/img]

[ 01-16-2006, 01:10 PM: Message edited by: gert ]

[gert]

actualy fairing lines on acad sucks.
I just drew all the stations out (on CNC) for Grey Seal full size on a sheet of black melamine (glue up table); there were 3 "bumps" on 3 stations.
I went back to my 19" monitor and they are not apparent.
Nothing a bendy stick won't fix [img]tongue.gif[/img]

[ 01-16-2006, 01:10 PM: Message edited by: gert ]

[Antonio Majer]

well, just to show what I have done in AutoCAD for my 14’ peapod, following Gardner’s offsets. In his books Gardner is always very careful, I didn’t need to fair the lines so much.

First I have drawn simple straight polylines, passing through each points of the offsets table; then I have “fitted” them via the Pedit/Fit command. I didn’t use the Pedit/Spline option, because a polyline doesn’t pass through those points any more after having been “splined”, while a “fitted” one does. For those who don’t know the problem, here there is a yellow straight polyline, a red arc-fit polyline and a magenta spline polyline (both gotten from the yellow one)



If one stretches the magenta spline, in order to make it pass through the old points, loses the original offsets (well, this is my experience, maybe I’m wrong).
Anyway it’s a matter of choice, in my opinion arc-fit polylines and spline-polylines aren’t so different when the curvature is small. To control the hull, I have drawn a mesh-surface between the longitudinal lines (edgesurf command), and then shaded it. If there are humps or dips on the hull surface, they can be found easily (via Orbit command) and corrected. Then I drew the sections of the planks at each station, plus some sections between the stations. Gardner gives a table of the widths of the planks at each station, hence I didn’t need to try for the best lining (well, for this particular boat, Gardner says it would have been better to line the first 2-3 planks slightly wider, but I preferred not to change anything).



When the plank sections are drawn, it is possible to join the sections of each plank with a surface. I decided to draw the outer face of the plank; probably it isn’t so important, the length difference between outer and inner face is minimal. I think in a caravel planked boat it’s mandatory the outer face, but I have never tried, by now - hope to loft a Whitehall this way, sooner or later. By exploding a mesh-surface, one gets 3D-faces, which cannot be exploded further and are not coplanar. It’s necessary to convert that mesh-surface into a wire frame of true lines, and to add a diagonal to each mesh to get coplanar figures, i.e. triangles; one has to trace those 3D-faces again, using simple lines (well, a lisp or VBA sub can do the job in a while). Then it’s possible to move each triangle from the XYZ space onto the XY plan via the Align command, and to get the development of the planks on the plan.



I plotted them in scale 1:1 clipping and hanging them on the molds for control (here you see a quick 1:10 half model too); I could build the planks all in one go.



AutoCAD is a wonderful software, last year I cross upgraded from AutoCAD2002 to ADT2005, an AutoCAD-based software for civil architecture/engineering, and I’m finding it astonishing.

[Antonio Majer]

well, just to show what I have done in AutoCAD for my 14’ peapod, following Gardner’s offsets. In his books Gardner is always very careful, I didn’t need to fair the lines so much.

First I have drawn simple straight polylines, passing through each points of the offsets table; then I have “fitted” them via the Pedit/Fit command. I didn’t use the Pedit/Spline option, because a polyline doesn’t pass through those points any more after having been “splined”, while a “fitted” one does. For those who don’t know the problem, here there is a yellow straight polyline, a red arc-fit polyline and a magenta spline polyline (both gotten from the yellow one)



If one stretches the magenta spline, in order to make it pass through the old points, loses the original offsets (well, this is my experience, maybe I’m wrong).
Anyway it’s a matter of choice, in my opinion arc-fit polylines and spline-polylines aren’t so different when the curvature is small. To control the hull, I have drawn a mesh-surface between the longitudinal lines (edgesurf command), and then shaded it. If there are humps or dips on the hull surface, they can be found easily (via Orbit command) and corrected. Then I drew the sections of the planks at each station, plus some sections between the stations. Gardner gives a table of the widths of the planks at each station, hence I didn’t need to try for the best lining (well, for this particular boat, Gardner says it would have been better to line the first 2-3 planks slightly wider, but I preferred not to change anything).



When the plank sections are drawn, it is possible to join the sections of each plank with a surface. I decided to draw the outer face of the plank; probably it isn’t so important, the length difference between outer and inner face is minimal. I think in a caravel planked boat it’s mandatory the outer face, but I have never tried, by now - hope to loft a Whitehall this way, sooner or later. By exploding a mesh-surface, one gets 3D-faces, which cannot be exploded further and are not coplanar. It’s necessary to convert that mesh-surface into a wire frame of true lines, and to add a diagonal to each mesh to get coplanar figures, i.e. triangles; one has to trace those 3D-faces again, using simple lines (well, a lisp or VBA sub can do the job in a while). Then it’s possible to move each triangle from the XYZ space onto the XY plan via the Align command, and to get the development of the planks on the plan.



I plotted them in scale 1:1 clipping and hanging them on the molds for control (here you see a quick 1:10 half model too); I could build the planks all in one go.



AutoCAD is a wonderful software, last year I cross upgraded from AutoCAD2002 to ADT2005, an AutoCAD-based software for civil architecture/engineering, and I’m finding it astonishing.

[John Meachen]

I know a little about Autocad and it is obvious that Antonio is an expert.I would like to thank him for his excellent description of the processes he used.It would take a novice like me several months to learn to produce what has been documented and it would be a very valuable experience.This is the first and only account that I have seen in which the process of determining plank shape has been described.We can also see from the end result that it works.

[John Meachen]

I know a little about Autocad and it is obvious that Antonio is an expert.I would like to thank him for his excellent description of the processes he used.It would take a novice like me several months to learn to produce what has been documented and it would be a very valuable experience.This is the first and only account that I have seen in which the process of determining plank shape has been described.We can also see from the end result that it works.

[Ken Hutchins]

Nice work Antonio. [img]smile.gif[/img] I especially like the layouts for the planks. [img]smile.gif[/img]

[Ken Hutchins]

Nice work Antonio. [img]smile.gif[/img] I especially like the layouts for the planks. [img]smile.gif[/img]

[Dave Fleming]

I sure wish I knew what you guys is talkin' about?

That CAD stuff that Antonio posted looks mighty slick.

Antonio, you got the plank layout right from the CAD input? Did you make some mylar drawings/templates cut use in cutting them out?

[Dave Fleming]

I sure wish I knew what you guys is talkin' about?

That CAD stuff that Antonio posted looks mighty slick.

Antonio, you got the plank layout right from the CAD input? Did you make some mylar drawings/templates cut use in cutting them out?

[Antonio Majer]

Thank you so much. I have been using AutoCAD since 1990 (R10). Anyway I think that everybody can do this job, it isn’t true design, but lofting, isn’t it? I mean, Gardner is always clear and careful, I have only summed up his work. Dave: I plotted on paper (pretty heavy, 120g/m², sorry it’s to hard for me to convert it in lb/square feet), mylar costs lots of money. I was thinking that maybe one could “fix” the paper with a spray painting, but I never tried. Anyway it would be interesting to know the possible max dilatation of those strips of paper, I bet it is less then the accuracy of the execution.





Edit to add:
Dave, I think the more a software is useful, the more is potentially dangerous. One has simply to dominate his tools, otherwise they dominate him. Probably one needs more time to master a software then a pencil, which we start using when we are 2-3 years old, but it's only a matter of time. What should we say about the piano, then? probably the piano is the most tortuous and oddest machine ever invented, it takes 10 years and more to be learnt, the most of students leaves, but nevertheless there are people that can express the shades of their feeling through it. So I think the only rule is not to take anything for granted.

[ 01-21-2006, 09:51 AM: Message edited by: Antonio Majer ]

[Antonio Majer]

Thank you so much. I have been using AutoCAD since 1990 (R10). Anyway I think that everybody can do this job, it isn’t true design, but lofting, isn’t it? I mean, Gardner is always clear and careful, I have only summed up his work. Dave: I plotted on paper (pretty heavy, 120g/m², sorry it’s to hard for me to convert it in lb/square feet), mylar costs lots of money. I was thinking that maybe one could “fix” the paper with a spray painting, but I never tried. Anyway it would be interesting to know the possible max dilatation of those strips of paper, I bet it is less then the accuracy of the execution.





Edit to add:
Dave, I think the more a software is useful, the more is potentially dangerous. One has simply to dominate his tools, otherwise they dominate him. Probably one needs more time to master a software then a pencil, which we start using when we are 2-3 years old, but it's only a matter of time. What should we say about the piano, then? probably the piano is the most tortuous and oddest machine ever invented, it takes 10 years and more to be learnt, the most of students leaves, but nevertheless there are people that can express the shades of their feeling through it. So I think the only rule is not to take anything for granted.

[ 01-21-2006, 09:51 AM: Message edited by: Antonio Majer ]

[Bruce Taylor]

Very impressive, Antonio! I especially like how you defined plank and rabbet bevels. Thanks for the the mini-tutorial.

[Bruce Taylor]

Very impressive, Antonio! I especially like how you defined plank and rabbet bevels. Thanks for the the mini-tutorial.

[AHall]

Wow! Antonio: that is very impressive.
Thanks for showing us how it's done.

Cheers,
Andy Hall

[AHall]

Wow! Antonio: that is very impressive.
Thanks for showing us how it's done.

Cheers,
Andy Hall

[bainbridgeisland]

Originally posted by AHall:
Wow! Antonio: that is very impressive.
Thanks for showing us how it's done.

Cheers,
Andy Hall

I too think Antonio did a great job but I can't help but ask why? As an AutoCAD user at my work, I recognize how time consuming it is to do what Antonio did. Regular old lofting by hand would have been less time consuming.

In my opinion, computer lofting is only efficient if the electronic model is already in your computer. Further, AutoCAD is not a very good program for lofting. I use Rhinoceros 3d and it works O.K. with the right plug-ins. It is far, far faster to loft with it that with AutoCAD. Never the less, lofting by hand would still be faster than creating an electronic model from offsets and then lofting it electronically.

This is somewhat of an ongoing pet peeve of mine. Having lofted professionally both by hand and electronically, I just do not see why everyone wants electronic lofting. It isn't any better than hand lofting and commonly takes longer. The accuracy of the finished product is controlled far more by the construction tolerances than by the lofting tolerances. It only saves time if the plans are in electronic format to begin with.

David Mancebo

[bainbridgeisland]

Originally posted by AHall:
Wow! Antonio: that is very impressive.
Thanks for showing us how it's done.

Cheers,
Andy Hall

I too think Antonio did a great job but I can't help but ask why? As an AutoCAD user at my work, I recognize how time consuming it is to do what Antonio did. Regular old lofting by hand would have been less time consuming.

In my opinion, computer lofting is only efficient if the electronic model is already in your computer. Further, AutoCAD is not a very good program for lofting. I use Rhinoceros 3d and it works O.K. with the right plug-ins. It is far, far faster to loft with it that with AutoCAD. Never the less, lofting by hand would still be faster than creating an electronic model from offsets and then lofting it electronically.

This is somewhat of an ongoing pet peeve of mine. Having lofted professionally both by hand and electronically, I just do not see why everyone wants electronic lofting. It isn't any better than hand lofting and commonly takes longer. The accuracy of the finished product is controlled far more by the construction tolerances than by the lofting tolerances. It only saves time if the plans are in electronic format to begin with.

David Mancebo

[Ken Hutchins]

There are other benefits to having the electronic file such as someday making another boat, the same size or even a different size such as a model, plot - scale factor and your lofting is done. I did my boat design on AutoCAD and I'm mighty happy I did. I made a model first then the plot scale factor for the full size boat. [img]smile.gif[/img]
Other benefits, you have the electronic file to check dimensions, create details, etc. during your coffee breaks or in the evening while sitting at the computer instead of crawling around beating you knees on the loft floor, that's assuming of course you have the luxury of a loft floor, the computer file takes a lot less space and is a lot more comfortable to work at. Them knees can only take so much abuse.

[Ken Hutchins]

There are other benefits to having the electronic file such as someday making another boat, the same size or even a different size such as a model, plot - scale factor and your lofting is done. I did my boat design on AutoCAD and I'm mighty happy I did. I made a model first then the plot scale factor for the full size boat. [img]smile.gif[/img]
Other benefits, you have the electronic file to check dimensions, create details, etc. during your coffee breaks or in the evening while sitting at the computer instead of crawling around beating you knees on the loft floor, that's assuming of course you have the luxury of a loft floor, the computer file takes a lot less space and is a lot more comfortable to work at. Them knees can only take so much abuse.

[AHall]

David: I hear what your saying, My interest in Autocad lofting is mainly because I sit in front of a computer all day at work. When there is a little down time, I fool around with trying to view the sections of my boat on the computer screen. I don't plan to build from these renderings, but did hope to do some area calculations (for displacement) and just to see if it can be done. Antonio has shown me that it can, but is a lot of work.

I agree fully that it is a lot easier to loft on a floor the old fashion way.

Thanks,
Andy Hall

[AHall]

David: I hear what your saying, My interest in Autocad lofting is mainly because I sit in front of a computer all day at work. When there is a little down time, I fool around with trying to view the sections of my boat on the computer screen. I don't plan to build from these renderings, but did hope to do some area calculations (for displacement) and just to see if it can be done. Antonio has shown me that it can, but is a lot of work.

I agree fully that it is a lot easier to loft on a floor the old fashion way.

Thanks,
Andy Hall

[Antonio Majer]

Originally posted by bainbridgeisland:
In my opinion, computer lofting is only efficient if the electronic model is already in your computer. Further, AutoCAD is not a very good program for lofting. I use Rhinoceros 3d and it works O.K. with the right plug-ins. It is far, far faster to loft with it that with AutoCAD. Never the less, lofting by hand would still be faster than creating an electronic model from offsets and then lofting it electronically.

This is somewhat of an ongoing pet peeve of mine. Having lofted professionally both by hand and electronically, I just do not see why everyone wants electronic lofting. It isn't any better than hand lofting and commonly takes longer. The accuracy of the finished product is controlled far more by the construction tolerances than by the lofting tolerances. It only saves time if the plans are in electronic format to begin with.

David Mancebo

Thank you. I’m not a naval architect but I use AutoCAD at my work (building trade). AutoCAD – or the equivalent, obviously I’m not an AutoCAD vendor - is a general purpose software, the only one that a casual user/amateur ought to use, in my opinion. Your specific software is for naval architects or naval engineers, who can use it knowing what they are doing.
AutoCAD works for woodworking and for thousands other needs, I mean it’s somewhat a basic tool. Well, this is my opinion. Just out of curiosity, I have drawn that staff in a day, according to my work-diary.
---
About traditional lofting versus computer lofting for amateur boat builders, as usual there are advantages and drawbacks. Traditional lofting needs a whole room and ought to be done quickly (obviously one cannot take possession of a whole room for weeks only because it’s lofting time). Moreover it’s done on paper, which can be damaged in every day life. A computer can be used at every hour, and for most of us is our usual work-tool: I for one have gotten more familiarity with my computer then with the old dear pencils, maybe sharpened by hand (and I’m told to be an architect). A file grows slowly, one can work for few minutes every day. Since the golden method is always “to try and to try again”, even in the computer age, a file can be duplicated and permits more then one solution. A computer stores information, while my old traditional drawings are lost somewhere. A computer drawing can be plotted more then one time, while a traditional drawing is often felt like a sort of work of art (I’m joking).
---
The main drawback is known: computers give false certainties. Moreover one may lose the direct contact with his work, I mean a traditional drawing can be touched, there is (please do not laugh) a direct and in some way sensual relation with the object of our work. A pretty famous naval architect of my region (Carlo Sciarelli, Pardey cites him in his book) is told to be able to recognize boats which were designed by a computer from those designed traditionally (obviously he disregards the first ones); I think the half model – and traditional models in general – are essential for those who use a computer.

[ 01-22-2006, 08:31 AM: Message edited by: Antonio Majer ]

[Antonio Majer]

Originally posted by bainbridgeisland:
In my opinion, computer lofting is only efficient if the electronic model is already in your computer. Further, AutoCAD is not a very good program for lofting. I use Rhinoceros 3d and it works O.K. with the right plug-ins. It is far, far faster to loft with it that with AutoCAD. Never the less, lofting by hand would still be faster than creating an electronic model from offsets and then lofting it electronically.

This is somewhat of an ongoing pet peeve of mine. Having lofted professionally both by hand and electronically, I just do not see why everyone wants electronic lofting. It isn't any better than hand lofting and commonly takes longer. The accuracy of the finished product is controlled far more by the construction tolerances than by the lofting tolerances. It only saves time if the plans are in electronic format to begin with.

David Mancebo

Thank you. I’m not a naval architect but I use AutoCAD at my work (building trade). AutoCAD – or the equivalent, obviously I’m not an AutoCAD vendor - is a general purpose software, the only one that a casual user/amateur ought to use, in my opinion. Your specific software is for naval architects or naval engineers, who can use it knowing what they are doing.
AutoCAD works for woodworking and for thousands other needs, I mean it’s somewhat a basic tool. Well, this is my opinion. Just out of curiosity, I have drawn that staff in a day, according to my work-diary.
---
About traditional lofting versus computer lofting for amateur boat builders, as usual there are advantages and drawbacks. Traditional lofting needs a whole room and ought to be done quickly (obviously one cannot take possession of a whole room for weeks only because it’s lofting time). Moreover it’s done on paper, which can be damaged in every day life. A computer can be used at every hour, and for most of us is our usual work-tool: I for one have gotten more familiarity with my computer then with the old dear pencils, maybe sharpened by hand (and I’m told to be an architect). A file grows slowly, one can work for few minutes every day. Since the golden method is always “to try and to try again”, even in the computer age, a file can be duplicated and permits more then one solution. A computer stores information, while my old traditional drawings are lost somewhere. A computer drawing can be plotted more then one time, while a traditional drawing is often felt like a sort of work of art (I’m joking).
---
The main drawback is known: computers give false certainties. Moreover one may lose the direct contact with his work, I mean a traditional drawing can be touched, there is (please do not laugh) a direct and in some way sensual relation with the object of our work. A pretty famous naval architect of my region (Carlo Sciarelli, Pardey cites him in his book) is told to be able to recognize boats which were designed by a computer from those designed traditionally (obviously he disregards the first ones); I think the half model – and traditional models in general – are essential for those who use a computer.

[ 01-22-2006, 08:31 AM: Message edited by: Antonio Majer ]

[Bruce Taylor]

When there is a little down time, I fool around with trying to view the sections of my boat on the computer screen. I don't plan to build from these renderings, but did hope to do some area calculations (for displacement) and just to see if it can be done

AHall, It sounds like you just need a good 3D hull modeller with basic hydrostatics. For these purposes, FREE!ship would be ideal.

It's not a lofting tool, but it can export files to AutoCAD (and Rhino, for that matter). It also automatically develops plates (w/ full offsets) for multichine construction. Here's the canoe I posted above, broken down into panels:



And, since the subject of fairing on computer has come up...

For fairing ordinary curves, FREE!ship offers a "control curves" feature that exaggerates degrees of curvature at points all along a given line.



For analyzing the curvature of the 3D surface, FREE!ship (like Rhino, I believe) has a Gaussian curvature routine that clearly flags lumps and hollows in the hull:



[ 01-21-2006, 07:00 PM: Message edited by: Bruce Taylor ]

[Bruce Taylor]

When there is a little down time, I fool around with trying to view the sections of my boat on the computer screen. I don't plan to build from these renderings, but did hope to do some area calculations (for displacement) and just to see if it can be done

AHall, It sounds like you just need a good 3D hull modeller with basic hydrostatics. For these purposes, FREE!ship would be ideal.

It's not a lofting tool, but it can export files to AutoCAD (and Rhino, for that matter). It also automatically develops plates (w/ full offsets) for multichine construction. Here's the canoe I posted above, broken down into panels:



And, since the subject of fairing on computer has come up...

For fairing ordinary curves, FREE!ship offers a "control curves" feature that exaggerates degrees of curvature at points all along a given line.



For analyzing the curvature of the 3D surface, FREE!ship (like Rhino, I believe) has a Gaussian curvature routine that clearly flags lumps and hollows in the hull:



[ 01-21-2006, 07:00 PM: Message edited by: Bruce Taylor ]

[Bruce Taylor]

Your specific software is for naval architects or naval engineers, who can use it knowing what they are doing.

Antonio, Rhino 3D isn't just a naval program, but an all-purpose 3D modelling tool. It's quite popular with amateurs (and for good reason, I think...it's extremely easy to learn).

[Bruce Taylor]

Your specific software is for naval architects or naval engineers, who can use it knowing what they are doing.

Antonio, Rhino 3D isn't just a naval program, but an all-purpose 3D modelling tool. It's quite popular with amateurs (and for good reason, I think...it's extremely easy to learn).

[RodB]

I'm wondering what would be the advantages of lofting on the computer if only building one boat?

A boatbuilder I know is a mechanical engineer and I think he kinda redesigns a boat he is going to build (inputting it into the computer in CAD)... using his files to have many parts cut cnc...etc I guess he sees the process of inputting the design into CAD as worthwhile compared to lofing the design manually. .,.and I assume he hopes to make some money for his computer time if another builder comes along later on...not to mention the accuracy of the cnc cutting of his many parts including the molds. I'm not talkiing about the many designs for sharpies etc of today that have cnc panels available in kits for a design...I'm talking about a traditional design with round bilge...

The computer is a great tool in the hands of the experienced designer as they can make changes and see immediately how many calculations/specs are affected. I have seen the case made for the computer as really a great advancement over the ways of old, but one must not only be a master of NA, but also a master of the computer software to do the design work. ..See the following thread:

http://www.woodenboat-ubb.com/ubb/ultim atebb.php?ubb=get_topic;f=1;t=012994

As a digital imager I can see the attraction of using the computer to loft designs, especially if you were going to use such a tool for ease of producing the molds, etc on cnc machines.... I know several designs I have looked at over the past couple of years had computer lofting available. You just have to decide whether your time is more valuable than the cost of the cnc files of the design, the cost of the cnc cutting, etc.

All in all, I would want to get a solid education in Naval Architecture to really enjoy the process of trying to actually design a boat, as you would need that to have any idea of what you are actually doing. I would compare it to trying to build a Winchester model 21 side byb side shotgun stock on your own, with little experience...just reading a few books....(double gun stocks are very difficult to make properly and take years of experience).

I realize many on this forum like to play with design and I applaud them for their efforts. For me, the necessary knowledge would be a large barrier. I see this as generally why many "would be boatbuilders" usually select a design to build from a '"master" because the design just "worked" and has a record of great performance as proof. Additionally, designs of special note like L Francis's "Rozinante", or Nat's "Alerion" and "Pleasure", and Peterson's schooner "Susan", etc were based on a lifetime of experience and turned out pretty damn good if not great. I guess thats why I have never been seriously interested in playing around with designing... just refining criteria for a design or modificatons... that could be worked up by a professional.

So what would be the advantages of lofting the design on the computer instead of a lofting surface by hand?...if you weren't going to build but one boat? I realize if the entire boat was designed in the computer you could save lots of time in not having to loft her, but it would seem to take a lot of time to input her into the computer compared to just lofting by hand.

RB

[ 01-22-2006, 11:24 PM: Message edited by: RodB ]

[Antonio Majer]

Originally posted by RodB:
I'm wondering what would be the advantages of lofting on the computer if only building one boat?

I wonder if it makes sense to discuss this issue from a utilitarian point of view then. Gardner says that Time – for amateur boat builders – is worth nothing; in fact building is somewhat an act of love, Time shouldn’t matter so much. A software is a tool, if one enjoys it, one uses it. Anyway a computer drawing can be plotted in scale, say 1:10 or 1:5, to build a scaled model. This is a key advantage, in my opinion. General speaking, I don’t like Renderings, Virtual Reality, and alike, it’s stupid computer game, in my opinion. Well, I know they serve to sell one’s ideas, sometimes a client is an idiot. But I for one like true drawing, I mean: made by true lines and true arcs, i.e. the abstract representation of a concept. From this point of view, I don’t find such a great difference between computer drawings and traditional drawings.

[RodB]

I'm wondering what would be the advantages of lofting on the computer if only building one boat?

A boatbuilder I know is a mechanical engineer and I think he kinda redesigns a boat he is going to build (inputting it into the computer in CAD)... using his files to have many parts cut cnc...etc I guess he sees the process of inputting the design into CAD as worthwhile compared to lofing the design manually. .,.and I assume he hopes to make some money for his computer time if another builder comes along later on...not to mention the accuracy of the cnc cutting of his many parts including the molds. I'm not talkiing about the many designs for sharpies etc of today that have cnc panels available in kits for a design...I'm talking about a traditional design with round bilge...

The computer is a great tool in the hands of the experienced designer as they can make changes and see immediately how many calculations/specs are affected. I have seen the case made for the computer as really a great advancement over the ways of old, but one must not only be a master of NA, but also a master of the computer software to do the design work. ..See the following thread:

http://www.woodenboat-ubb.com/ubb/ultim atebb.php?ubb=get_topic;f=1;t=012994

As a digital imager I can see the attraction of using the computer to loft designs, especially if you were going to use such a tool for ease of producing the molds, etc on cnc machines.... I know several designs I have looked at over the past couple of years had computer lofting available. You just have to decide whether your time is more valuable than the cost of the cnc files of the design, the cost of the cnc cutting, etc.

All in all, I would want to get a solid education in Naval Architecture to really enjoy the process of trying to actually design a boat, as you would need that to have any idea of what you are actually doing. I would compare it to trying to build a Winchester model 21 side byb side shotgun stock on your own, with little experience...just reading a few books....(double gun stocks are very difficult to make properly and take years of experience).

I realize many on this forum like to play with design and I applaud them for their efforts. For me, the necessary knowledge would be a large barrier. I see this as generally why many "would be boatbuilders" usually select a design to build from a '"master" because the design just "worked" and has a record of great performance as proof. Additionally, designs of special note like L Francis's "Rozinante", or Nat's "Alerion" and "Pleasure", and Peterson's schooner "Susan", etc were based on a lifetime of experience and turned out pretty damn good if not great. I guess thats why I have never been seriously interested in playing around with designing... just refining criteria for a design or modificatons... that could be worked up by a professional.

So what would be the advantages of lofting the design on the computer instead of a lofting surface by hand?...if you weren't going to build but one boat? I realize if the entire boat was designed in the computer you could save lots of time in not having to loft her, but it would seem to take a lot of time to input her into the computer compared to just lofting by hand.

RB

[ 01-22-2006, 11:24 PM: Message edited by: RodB ]

[Bruce Taylor]

General speaking, I don’t like Renderings, Virtual Reality, and alike, it’s stupid computer game, in my opinion. Well, I know they serve to sell one’s ideas, sometimes a client is an idiot. But I for one like true drawing, I mean: made by true lines and true arcs,

For the designer, the ability to rotate a 3-dimensional model is very useful indeed. A wireframe or shaded image is less informative than a wooden half model, perhaps, but much easier to make (and remake). The perfect plasticity of the 3D computer hull is nice, of course, but the real payoff is in the ready access to hydrostatics data. Feedback is immediate: pinch the hull here, the LCB moves there...puff out the bilge, and watch the DWL go down.

In any case, there's no need to choose between "renderings" and "drawings." Nautical design software that can be used to draw a pretty picture of a boat in a sunset will also generate a clear linesplan, sectional diagrams, tables of offsets, etc.

As for lofting...we all have different needs, skills, and preferences. I wouldn't bother to transfer an old set of plans to CAD unless I were interested in making significant changes to the design. It's just too easy to buy a few sheets of doorskin and get down in my knees for a few hours.

However, if I already had the design in digital form (and these days a lot of boats are born in CAD) why wouldn't I print up patterns for moulds (or even have them cut in CNC, if it were cheap and available)?

Antonio's method obviously worked for him. Well done, I say!

BTW, RodB...thanks posting that link to the thread describing Hesp's Hope. Very interesting!

[ 01-23-2006, 09:34 AM: Message edited by: Bruce Taylor ]

[Antonio Majer]

Originally posted by RodB:
I'm wondering what would be the advantages of lofting on the computer if only building one boat?

I wonder if it makes sense to discuss this issue from a utilitarian point of view then. Gardner says that Time – for amateur boat builders – is worth nothing; in fact building is somewhat an act of love, Time shouldn’t matter so much. A software is a tool, if one enjoys it, one uses it. Anyway a computer drawing can be plotted in scale, say 1:10 or 1:5, to build a scaled model. This is a key advantage, in my opinion. General speaking, I don’t like Renderings, Virtual Reality, and alike, it’s stupid computer game, in my opinion. Well, I know they serve to sell one’s ideas, sometimes a client is an idiot. But I for one like true drawing, I mean: made by true lines and true arcs, i.e. the abstract representation of a concept. From this point of view, I don’t find such a great difference between computer drawings and traditional drawings.

[Antonio Majer]

Bruce, btw, I was not thinking of your naval software obviously, but of architectural rendering (in the case, sorry [img]smile.gif[/img] for my ambiguity). Nevertheless I think that the Virtual image af something, is Virtual, not real, and may be misleading for this reason.

[ 01-23-2006, 09:48 AM: Message edited by: Antonio Majer ]