Surfacing... just a nightmare

Rhino Rhino for Windows
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Kappa value measures the change of tangent vector as a function of arc length along curve.

In case of circumference, value is 1 (constant). Everything multiplied by 1 remains unchanged. Constant change. Values below 1 state that change is decreasing. Above 1, increasing.

0.0 change means cero. Everything multiplied by cero gives cero.

Kappa considers the POSITION of a floating point along curve, defined either by arc length of curve (s) or T parameter.

e.g. let’s say we have identical curves were identical rate of change. However, their scaling is different. If u analyze. One curve will bend more sharply than the other, for sure. For every x unit of arc length (s), curves will present a different rate of change in tangent vector. Be careful, T parameter works as “percentage” of arc length! If we consider T parameter, formula must be redefined differently. To compare rate of change of tangent vector, floating points must not be positioned relatively or geometrically.

Then kappa value is translated to a curvature measure, an osculating circle perhaps. Rearranging formulas you’ll get that kappa value equals the reciprocal or inverse value of radius.

The formula for kappa only works for non-zero values.

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1/0 units = undefined

But, you can cheat! You may approximate this within file tolerance. e.g;

Tolerance set to .0001 units

1/0.0001 units = 10.000

Radius of osculating circle at end point Pt equals 10.000 units (almost flat curved area). As a result, zebras will display sleek lines!

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The end?

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Hooo, Tancredi de Aguilar was one of my awesome professors.

Yes, artist car designers as me, make the concept of the car using Rhino and then we feed CATIA and ALIAS modelers with IGES to create final and class A.

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Can I ask if it is not possible at all to do all the work from start to finish inside rhino ? Or is it a company need for communication with other software?

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Depend on what you mean for from start to finish.
Yes, I was able to use Rhino for all the processes In a small team environment. Grasshopper now lets you more autonomy for automation improvement. And if you know how to avoid bugs you can also use it for hard surface game development as well as creating a complex sailboat.

But, in general, there is big tradition inertia and cad modeler(alias), engineers(catia) are more comfortable using specific tools for the task. It depends on what type of work. If the factory is big, there is big liberty of assets, know-how knowledge, and traditional workflow. There is no time for experimenting with newer software tools like Rhino unless the new employee is bringing faster better workflow know-how. So slowly Rhino grows in the sector of what is capable of. We often switch between Rhino and Alias in design department and feed CATIA or Solidworks.

In other words, If you are designer chances are that old colleges just use only paper. So Rhino fits well. But if you are an engineer, your college will not agree. I’m not an engine engineer. As a car designer, I was always able to feed them with Rhino interior and exterior models. A probably Rhino exterior example made by Pic and Pop close start to finish

PopAndPic
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Well, I am finishing my naval engineering course (it is a mix between marine engineering and naval architecture) and I heard since day one of my course how I should practice and get comfortable with Rhino because all shipyards use it and stuff.

I was starting to do so, but I got an internship in the college engineering department and they used Solidworks heavily, so I focused on getting good on what I was using, but I always kept thinking about Rhino, then that internship ended 2 years later>

I was about to seek the rhino training again but I got selected for a scientific initiation program, basically its an internship to learn how the researching side of the college works to see if I would like it and seek an masters to become teacher or something, I did heavy programming in Pascal/Delphi, some C++ and Python for another year and a half and Rhino got left behind again, that ended as well

I was in need of money, so applied for an internship on the IT department where I did a lot of user support and also, given my programming knowledge, helped with some internal system stuff, for another year, and Rhino got left behind again.

Finally I was in last year and I got an internship in a Shipyard, and had a month of extensive Rhino modelling with all tutorials I could get to get ready for it, and I loved using Rhino with all my passion, It was a bumpy ride, but was 100x more enjoyable and stress free than using surfacing inside solid (it get the job done but… with a heavy price in sanity, IMO) and since all my teachers said it was absolutely, I was thrilled to start working in the shipyard.

When I started it, they were using mostly Solidworks (in a so wrong and messy workflow that is hard to even describe, to this day I still have nightmares with missing references and tree error from start to finish in 300 ish commands list)

I kinda still push the Rhino usage, and one of our third parties use as its main tool, so I am the one receiving all those files.

I know Rhino is not suppose to be an engineering tool as other solid modellers sell themselves, but the versatility and robustness is so freaking amazing that I feel dirty using any solid modeller.

I just asked about start to finish, in hope to get some knowledge of some plugin or workflow that really makes rhino shine, I even started using Rhino for document and presentations, using Picture Frame and layers for it (come at me LayerBook).

I am also trying to learn grasshopper to incorporate in my workflow, and also Fologram.

So please, if you, or anyone that reads this, with the amazing experience of these forum users combined, please share your knowledge with us, new(ish)comers.

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Ships from start to finish can use rhino. Because the shapes can be complicated, using solidworks or something can be a nightmare, which you found.

Glosten is a good example of this.

There are some advanced workflows that have developed around Rhino for Marine:

  1. Use Orca3d for fairing trims and weight and cost tracking
  2. Use CFD studies using OrcaCFD
  3. Damage stability can be done by exported a GHS file with compartments and tanks.
  4. Use Express Marine to define the structure parametrically in Rhino.
  5. Export the structural model directly to ShipConstructor with all the information for production at the larger shipyard level. This new process saves tons of time.

Of course this assumes ships beyond medium sized workboats. Much of the small to medium work is done in Rhino directly.

Of course composite yachts under about 200’ also are mostly done just in Rhino with the use of Autocad from drawings, or the 3d models send directly to the mold makers.

Fologram is a very cool way to interact with the 3d model and the physical existing structures you might be doing on a retrofit.

The guys at Orca are the real experts and they can help answer any process questions you have as you are looking to improve your current workflows.

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Well, actually the hull is better to use Solidworks because Rhino is not capable and then passes that first surface to Rhino to built up all the rest.
@scottd In Rhino is missing a second-degree network tool!
And almost all this is made using rhino [link] but I’m struggling because I use second-degree surface in one direction. Grasshopper now covers up this gap.

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Thanks,

I Do own a personal Orca3D license, still learning how to properly use it, and I am doing my final work for the university using OrcaCFD, again, still learning the do(s) and don’t(s) with it, and for sure I am getting ahead of myself asking these kind of questions that for sure will get me complicated answers.

Orca3D’s team does keep up with McNeel amazing support, it looks like there is never a bad time for you guys.

But I think I got ahead of myself, I will try to make a future post being more specific about this, it is kinda off topic for what this topic was first created.

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So are you saying with Grasshopper you can get what you want? That is great. Good reason to use Grasshopper.

Normally I do not use network surface, too much fitting noise when fairing hulls. Just using direct surface manipulation works most of the time.

But a blanket statement about the marine industry is difficult. The discussion here is a great example. Many if the tools we use are now talking design requirements, fabrication method downstream partners, etc…

As you get out into new companies where you feel the workflow is complicated and too difficult knowing all these different methods can be super helpful.

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Alan,
The problems associated with fair hull creation in Rhino are not trivial. I gave up with Rhino because of the difficulty of mouse clicking on planes at odd angles in 3D space. Thats where Grasshopper entered the picture

The other benefit of Grasshopper is that is a FULLY PARAMETRIC tool. Rhino interface is not.

But even better than that, in Grasshopper, every step from points to curves to surfaces to solid hulls is preserved for you to walk back through and rework at any point.

I struggled with a fair round bilge for months. I tried many approaches. Most of the suggestions you will find here are either simplistic, inadequate or require extensive fabrication time.

With GH, Rhino can turn out a hull that is better than any mouse clicked interface including Catia.

With respect to Orca3D, I was a little underwhelmed with this and just about every other software tool for boat design, evaluation and construction. These tools require extensive data entry, most of which you are trying to get FROM the software not put in to it.
The hull design tool is primitive and certainly doesnt to sophisticated round bilge hulls of constant radius. Its also pricey.

I strongly recommend RhinoHyd for Rhino 6. It does the Intact Stability analysis very nicely. Its simple and FREE
http://pingud.com/download/

I have tried all the tools I could find and I keep coming back to Grasshoper. You can bend it to do modeling, create very accurate weight and CG analysis, Structural analysis and plug ins that can calculate bending loads etc.

You cn do all this in GH AND have access to all the pts. curves and surfaces for other operations. Im no knocking this product, but olike maxsurf, you gotta learn the way it works, what its limitations are (and there are always some) and then you married to it. GH comes with Rhino. How can ya beat that!

Just about every tool I have looked at that tries to make a software program around these requirements has serious limitations. MaxSurf structural analysis simply works its way through a mesh calculating loads and bending as it goes using FEA, but it chokes at a full ship with structural detail of the beams and their joints, so its virtually useless. GH can do simplified modelling better and faster.

Frankly, I dont know why McNeel doesnt just retire the Rhino interface and offer a rebranded, parametric product around Grasshopper with Rhino providing the viewports for GH. GH is undoubtedly the jewel in the crown. If I had begun w GH I would have shaved years off the learning curve

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I use “Network surface” in one of the following occasions:

  1. When I want to build some basic surface not possible with other Rhino tools, then I convert it via “Rebuild surface UV” and then apply “Match surface” with various options.
  2. When I want to build a surface with questionable quality just for fun. :slight_smile:
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I fight with the rebuild uv command … its behavior drives me crazy … it turns all surfaces into degree 3 it’s the only downside .
networksurf is good for certain situations my best command are lofts and edgsurf , they inherit the topology of the curves
. in my opinion rhino is in urgent need of good surfacing improvement .

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Yes, is exactly what I was trying to explain. Plus is very customizable for each particular client workflow.

@Rhino_Bulgaria Yes “Network” is almost not useful and this confuses new users.

Almost all my surfaces are built up in this way:

image
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But in my way of doing this clean surface, if I move just one point, any, I need to update all the other surfaces. That means the hole model including trim and connected surfaces. And that is a nightmare for me. @scottd Grasshopper is part of the solution but is very very slow because I need a lot of connected surfaces to update. And so is not viable.
That is the reason why I’m asking for a Grasshopper compiler so that it runs faster (all the model on stack and the heap) and pushing for a SubD of second-degree that is missing, important to cut time.

To fix nightmare THIS IS MY WISH SINCE 90s LINK <---------------------<<< [¡¡¡ WISH FEEDBACK!!!]

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Define “a lot”?

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One complete wheel rim poly-surface.
I was not going more complex than this because was getting slower: https://forum.unity.com/threads/wip-gogo-tires.783767/
But if I do a Ferrari wheel I probably divide it in independent Grasshopper graphs. Because as a designer, you move a lot of points searching for the volume that actually works in all views. Probably what is missing in Grasshopper is a sort of cash optimization, that extrapolate just the data that will be updated, putting it into an inline array with better memory management and making just the job modification of only that data needed (that is not much) in sequence instead of prepossessing the hole object containing sub nested objects full of variables that essentially you will not change. I ask Unity that, like many others, and Unity thankfully came out with this: link example

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@DavidRutten [Sci-Fi idea] Now I’m wondering, since the mouse is now connected directly to the GPU, bypassing the CPU; If instead of a traditional C, a shader graph is use instead to make the red Grasshopper surface mesh,… I mean using shader language to build the mesh directly. You bake the final surface just one only when you press the button as you do now. But you can update more complex models by working actually only on the GPU mesh bypassing compliantly the CPU. In other words building the red mesh inside the GPU via shader. And using the CPU to make the surface when you bake.

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Are you proposing we convert our multi-thousand line NURBS mesher, which relies on hundreds of other methods, from C++ into GLSL?

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I think he is, and I think you are on the verge of rejecting it out of hand as “too much work”. I think Alan has a very interesting idea with what sounds on the surface of it as having a lot of potential. I think it would be useful if you (and the rest of the team) adjusted your attitude to “probably a lot of work” and started giving it some serious thought and consideration. After all, the “multi-thousand line NURBS mesher” probably took a lot of work. So did the conversion from ACIS and the Mac port. They turned out to be worth it. Perhaps after some serious consideration it will turn out that it’s not a great idea or doesn’t make any sense at all but at least we’ll know why.

Or maybe Alan and I just don’t know enough about the subject to understand why it’s a silly suggestion. I know I’d like to be enlightened if that’s the case.