Rhino for structure?

[ldigas]

Is Rhino adequate for structure modelling?

I'm making a comparison here to the Maxsurf suite in a way.

Rhino is more than fine (accurate too) for preliminary modelling, and for development of lines. But why do
I often see the comments that Rhino is not that adequate for structure modelling? What would be its
main drawbacks? What do people use for structure modelling and nesting, in smaller companies that works well with Rhino?

(in my case, so far ACAD)

[micspoko]

Rhino is good for modelling construction a small vessel but at larger construction its better to do in software designed for this type of task for example Napa

[pavel915]

For small boats structure of-course you can use rhino.
If you model every structural members by rhino solids then you can get the total weight and CG of the system. You can add openings or holes in rhino solids for creating cut-out of penetrating structures.
The main thing is, for structure of small boats its its much better to do the structure in Rhino instead of any 2d software like autocad, because using rhino for structure will give you the basic idea of the total structure of the boat.

[DavidJ]

Yeah you can use Rhino for structure. You can use a pencil to. It just depends on what you want to do, what your goals are, what your expectations are, etc.

I've done lots of structural modeling in Rhino and I find it very quick and easy to produce accurate models. For small refit projects or vessels requiring limited rework it is a very useful program. It works fine for large or small vessels with the key being the amount of potential changes/rework required. It's a pretty easy program for anyone with autocad skills to be able to pick up and learn. And since it is a completely open modeling program you can model anything you can imagine. In my point of view it's biggest drawbacks are it's lack of true parametric design and it's poor 2d conversion.

If you are doing detail 3d design of 40m+ ships then Rhino can be terribly inefficient. You can still do it but it is very time consuming. It isn't parametric, so changes mean starting over. You can't model one frame and then replicate it throughout the vessel the way you can with more sophisticated packages. It also doesn't lend itself well to being worked on by large teams of people. Bigger structure projects can have many individuals working on the same vessel and Rhino doesn't have the deep database built in to manage this type of work. Rhino also does not allow a collection of parts or sections to be saved and reused.

Other (much more expensive) packages I'm familiar with such as shipconstructor and the Catia structure module allow you to select a curve on the hull and with a couple of clicks you can tell the program that you want that curve to be a piece of 3 x 2 x 1/4 inch angle bar and then you can select the end and with a couple of more key presses you can select a sniped end cut. Hit okay and voila you have a perfectly modeled piece of structure. Brackets, rat holes, and cutouts can be added in the same way. Copy that to each frame and in minutes you have the simple structure for much of the vessel. In Rhino you'd have to draw the profile of the angle and sweep it (or otherwise model it) along the curve and then draw the end cut and trim that, resurface the cut to make it a solid and then do it all again for the next frame. Then say the owner decides that he wants the vessel to have a different class rating or to be a few feet longer or some other reason that your scantlings have to be recalculated. Say now you need a 4 x 3 angle. In Rhino my method is to scream a little bit inside and browse the internet until I've calmed down. Then I save a new copy of my model and erase all of my structure modeling down to the first curves and start again. In Catia I would select all of the affected pieces of structure, open up the dialog box and use the pull down menu to select 4 x 3 angle.

Even more powerful tools are available for the creation of 2D drawings. As pretty as 3D models are at the end of the day the boat/shipyards want traditional 2D drawings. Worse still they usually want very detailed 2D drawings. Everything in Rhino is very hands on. It is not much better than autocad or a pencil if at all for making 2D. If you want a 2D structure drawing then you make one. You use commands such as make2D to turn your model into 2D and then you spend a lot of time cleaning that up. Moving views, cutting, pasting, labeling, etc. Usually I export the Rhino 2D to autocad as I find it faster for detailing and laying out the drawings. You can probably expect to spend at least twice as long to turn your Rhino 3D into proper 2D construction drawings. But that time could easily skyrocket to 3, 4, 10+ times as long if more detail is needed or if the vessel is very large or very complicated. The automated drawing production in shipconstructor is an absolute work of art and a godsend to structural drafters. Parts can be automatically labeled, nested, and detailed assembly drawings produced with only a few clicks. Try keeping track of thousands of part numbers without a built in database - I've done it and it is a nightmare. Manual nesting - also not fun. Parts change shaper and need re-nesting - really really not fun.

So in short if you have a team of 30 engineers and drafters and you want to do detail production design of offshore supply vessels for yards with inexperienced crews, don't even considering using Rhino. If you want to design 30 foot yachts for reasonable clients to be built by experienced builders who don't need a lot of detail use Rhino (or even just autocad). If you are somewhere in between consult resellers and get some product demo's.