Full Version: Ship hull tutorials

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;)

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And generally when the calculus is not quasi immediate there is something wrong! :)

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Nothing against it, it's just that they suddenly do something fast that I miss or assume I realise!

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No problem!

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Hi, the network command need a very well coincident curves to avoid any deformation, the best workflow is making hull with the loft command a or with many patch and better curves, here you can see this made now in less than 15 min but I suggest to search for hull design for Rhino in YouTube ,there are many tutorials, and is very hard remaking hull from all the lines in the lines plan maybe, you can try selecting few of them for a better smooth surface otherwise it will be difficult to obtain a smooth surface, you must consider that the precision of the surfaces also depends on your precision in making the sections.

this hull is done with network curves and many blended surfaces and lofting on bottom hull
The lines are in the file

Attachments:
Test hull_edited.3dm

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And you can use this cool Function ! MoveSliceToPoint...if you have yet some documents...
http://moi3d.com/forum/messages.php?webtag=MOI&msg=2749.36
Video https://moiscript.weebly.com/deacuteplacer-des-objets.html
Sorry it's in French but very visual! ;)

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Hi Gordon, so the reason why Network is not working on your curves there is that your layout does not form a regular grid pattern which Network needs.

Part of a regular grid is that all of the curves in one of the 2 U/V sets should either all be closed or all be open.

In your case you have closed curves here:



And then an open curve here:



So because some are closed and some are open it won't work for all those curves to belong to the same direction set.

With this curve structure you would want it to be configured into pieces like this:





With it set up like that you would be able to use Network for one half of the hull.

However it's going to be messy because there is too large of a gap in this area:





There are some links to some previous discussion threads on ship hulls here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=3814.1

- Michael

Image Attachments:
gord_network1.jpg  gord_network2.jpg  gord_network3.jpg  gord_network4.jpg  gord_network5.jpg  gord_network6.jpg 

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Understood. I can now add a network. However, when I then try to join them, the don't always join up, or have holes at the joints.

Basically, I want to turn the thing into a solid so I can add details. I get joined surfaces but that is as far as I get.

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Hi Gord, it would probably be good to not try and bend the back part around 90 degrees like you are doing. Have it go straight back and then have a separate planar back end to it instead of trying to incorporate that into one single Network surfacing.

Right now you have a very dramatic shift in a small distance in this area:



That's too many things changing all at once - it's going to make a stressed and lumpy shape particularly in the lower area where it's being compressed down to a small area as well.

You can't get a good quality surface with that kind of high pressure shape changes in a small distance.

- Michael

Image Attachments:
gord_network7.jpg 

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OK, that works better now, thanks!

My next issue is I want to make it a solid so I can cut into it. The shell command does not seem to like it. I can put a lid and side on it, but it's still just joined surfaces, not a solid. I then need to mirror it into a full hull.

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Hi Gord, the shell command can only really handle thickening an open surface into a solid if it has all smooth pieces. When there are sharp edges like you have here the surface offsets do not touch each other and would need to be extended and intersected with each other and MoI's shell function is not good at doing that.

Additionally if you have any really tight bends or bumps in it that will be difficult for it to generate an offset surface from as well. An offset surface is generated by moving a distance away from the surface along its surface normal. If the surface normal is wiggling around chaotically it will become magnified in the offset and mess it up.

It's this area here that you have some of the most pronounced little bends and wiggles, but there are some wiggles in other areas too:



You'd need it to be a lot simpler, cleaner and less wiggly throughout for it to have any chance of generating good offset surfaces.

There's also a gap between some pieces here which will prevent it from being made into a solid:




For the back you'd want to do something like have a plane cut it off and then fillet that rather than trying to make a 3 sided network that has these little bends and folds in it:


3 sided networks can be problematic because the surface generated from it will have one of its sides collapsed down to a point and it is pretty easy for something with bends in it to then have really small tight bends in the collapsed down spot. Instead of a 3 sided network it is usually better to form areas like that by having a larger extended 4 sided surface that then becomes 3 sided by it being trimmed rather than trying to directly construct a surface to those curves. Then a fillet or blend can connect it to the other part. Something like more like this:






Another thing that's not so good is to have skinny fragments like these:




Those are probably caused by some of your curves that are being networked having sharp corners in them rather than being all smooth. Any segments in curves that are not smooth to their next or previous neighbor segment will divide the end network up at that sharp area.

Do you have the curves used to make this? If you can post those too I can take a look and see if I can call out any problems coming from them to start with.

- Michael

Image Attachments:
gord_shell1.jpg  gord_shell2.jpg  gord_shell3.jpg  gord_shell4.jpg  gord_shell5.jpg  gord_shell6.jpg  gord_shell7.jpg  gord_shell8.jpg  gord_shell9.jpg 

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The front piece is pretty good though. That section can be thickened like this:

First the front edge is very slightly wiggly. To straighten that out I selected the end surface control points and aligned them to be exactly vertical:



Then Construct > Offset to make an offset surface to the inside:



Edit > Trim the offset with a centerline:



This can now be mirrored and joined:



I then put in blends down here:



Then lofts for the thin "side wall" strips and then joined those in to make a solid. Hope that helps give a demo of how to go about that part.

- Michael

Attachments:
brede_front_thickened.3dm

Image Attachments:
gord_thickened1.jpg  gord_thickened2.jpg  gord_thickened3.jpg  gord_thickened4.jpg  gord_thickened5.jpg 

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The back portion is a little too lumpy near the back end to get a good offset surface, you might have too many curves back there or you're trying to bend it in too much to try and make the back end all in one go.

- Michael

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OK, I think I get it! I have no idea how these small sections and slivers arrive though. How can these be removed?

What commands/scripts can be used to equally space the nodes, and how to smooth the curves fairer?

The original lines are here.

Thanks for the help!

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In the past hull was drawn with flexible wood stick: that avoid little sharp curves! ;)
here not in wood! ;)


Esle when you ask "Show Points" you will see a red Square!
So multiple points are existing on the same x,xz place on the same curve !

So you must kill them
for example draw a little straight line for keep coordinates
kill all points then move the previous...
and kill the straight line! ;)

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Then select the curve
Press TAB
write rebuild (Rebuild ReBuild etc... but without space) and give a reasonable number of points by familly curves
you can make a shortCut on this Rebuild function just write Rebuild on the second column!

Make some zoom for see if there are no much points in some place
So here in the back deck
You can kill N° 1 , not 2 it's the vertical line, 3

etc...

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Then try to make very clean "patch" with intersection vertical horizontal and all will works fine! :)

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Rebuilt it all now, but used fewer waterlines.

Now I want it as a solid, but the shell offset won't have any of it.

Gord

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As the hull is difficult to close...

Just a little trick... ;)

More the hull and the line will be near better will be the result wanted... :)
That want not to say that the Hull is good but it's a solid! :)
https://moiscript.weebly.com/uploads/3/9/3/8/3938813/brede3.3dm
ps Not "Trim" but Boolean Diff of course else hull will be not closed! ;)

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Hi.

Not sure I understand what is happening here.

G

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