Hull wall thickness?

[QuarterMaster]

Finally getting a moment to respond on this....

First, the ability to easily do splined and blended body structures and do general design is a key feature that my ME likes. He does an incredible amount of fast concept and physical design development.

In a professional work environment this is important: "All licenses are permanent and do not expire. Prices include support and service releases for the current version. There are no maintenance fees."

The ME has had issues with dropped support for Autodesk SW products, including expiring licenses, forcing a complete new purchase or subscription for a running copy. He found the overall cost of ownership over time higher with Autodesk products than Rhino's model. My EX was an architectural designer...same complaints with AutoDesk. This was a major part of our adopting Rhino for our consulting work.

The ME uses his tools for hobby work, not just work. He has tried Fusion360, including the free version. free version limits too much of the capability, and he hates the user interface. I tried the free Fusion360 as well. I could not stand the interface, and couldn't do some of the operations I needed. Rather than risk messing with AutoDesk for an expensive subscription model, I have decided to go the Rhino route.

Still, it comes down to what you like and what you can afford.

Thank!

In the long run, if the SW is worth it, I'll pay the price.

I go by the old adage, "Feel the big pain once up front, or continue to feel multitude of pains afterward."

I LOATHE subscription licensing, more so being forced into it to give the a continuous stream of cash to the developer for little true benefit. I dig it, needs change, thing become antiquated, life EVOLVES, but man, I'd rather buy new software every five than leasing. As I tend to use 10-20% of a programs capabilities, new bells and whiskies often don't interest me. As long as they can correct bug's with free fixes, I'm good. But I also understand some people prefer renting rather than buying and can only afford that level.

Yeah, AUTODESK...I learned in the mid '90's at a Seminar the term, "Prisoner of Choices." as it tried to please EVERYONE. So I have my own beef.

Thanks again, I will to look into it.

[Thorbrandr]

How about some specifics regarding this decision, aside from the ME's(?) recommendation. Pro's, cons?

Finally getting a moment to respond on this....

First, the ability to easily do splined and blended body structures and do general design is a key feature that my ME likes. He does an incredible amount of fast concept and physical design development.

In a professional work environment this is important: "All licenses are permanent and do not expire. Prices include support and service releases for the current version. There are no maintenance fees."

The ME has had issues with dropped support for Autodesk SW products, including expiring licenses, forcing a complete new purchase or subscription for a running copy. He found the overall cost of ownership over time higher with Autodesk products than Rhino's model. My EX was an architectural designer...same complaints with AutoDesk. This was a major part of our adopting Rhino for our consulting work.

The ME uses his tools for hobby work, not just work. He has tried Fusion360, including the free version. free version limits too much of the capability, and he hates the user interface. I tried the free Fusion360 as well. I could not stand the interface, and couldn't do some of the operations I needed. Rather than risk messing with AutoDesk for an expensive subscription model, I have decided to go the Rhino route.

Still, it comes down to what you like and what you can afford.

[Subculture]

The limits on functionality for the free version are unlikely to bother most hobbyists in this game.

I did have a go with Rhino some years ago, but found it difficult, so it's horses for courses.

[Thorbrandr]

Working on this...been busy.

Fusion360 is free for a limited functionality for a limited time. Tried it. Did not like it. Also, the AutoDesk's reputation on policies on subscriptions and updates is not good. They have been known to ditch support for older subscribers and versions. Seen that from a few angles.

Will try to give more info on Rhino soon.

[Subculture]

Learning CAD is like learning a machine tool, you have to know what bits do what and the best techniques. I chose Fusion 360 because it seemed fairly intuitive, plus tons of tutorials online and it does most of what I would need it for.

The parametric design can get out of hand sometimes if you make an error early on.

Also I've yet to really get to grips with forms, and still get into a pickle with that. I mainly using it for certain parts and blend it with traditional hand-crafting to create what I'm after.

I think the software still has ways to go before it can be considered user friendly.

[Albacore 569]

Hi Bob,

I notice in your Argonaute Hull print in PVC material with it's 3 mm plus thickness you also laminated fiberglass cloth on top inside only too. I think that is an excellent idea for an extra measure of torsional stiffness without a lot of extra material. You're the experts, but I felt maybe that is an important factor to consider in this discussion perhaps too?

[jphatton]

I've been using Rhino since 2016 for CAD modelling and design. I settled on Rhino after testing some other CAD software, as it provided a good range of functionality was reasonable intuitive to learn and has with good help/tutorial support.

My primary interest up to now with CAD modelling has been to construct digital models to document things that interest me (submarines, sounding rockets and target drones to be specific :-), based on drawings and photos ie. integrating the reference material into a 3D model which can be used to document specific configurations which can then be used to generate derived drawings, cross sections or images. This year I finally got a 3D FDM printer and have started experimenting with printing the CAD models.

Rhino is one of the software used in naval design and building architecture, so has useful tools for modelling submarines. It uses NURBS rather than meshes to construct curves and surfaces and with experience it is possible to get smoothly lofted surfaces from construction curves (either classic lofts of cross sections, swept lofts along reference rails between sections or network surfaces built up from a series of intersecting curves). There is also a parametric modelling application called Grasshopper which is included in Rhino which can be used to generate models based on equations and varying input parameters. I made some quick models of various small axisymmetric AUV hulls using this method from Myring hull equations & NACA airfoil sections, as well as a reasonable approximation of a Thresher / Permit submarine hull using the Myring equations.

For 3D printing the files need to be exported as mesh files which is relatively straightforward but I found the default settings too coarse for printing, so this needs some adjusting to get right. However, you can visualise the 3D print in the slicer software before printing. A fairly comprehensive tutorial can be found here;

https://www.sculpteo.com/en/tutorial/rhino-3d-tutorial/

In addition there are a set of mesh tools for directly working with meshes or deriving things from them. Also there is good support for import and export of many other file formats.

Ultimately, the choice of which software to use for modelling comes down to what you want to do and how much time, effort and budget you want to invest. I assume that many of the other software out there can do similar things to Rhino & there are some good examples of CAD modelling work done with other packages on this forum.

The key thing is taking the time to learn the tools and build up the skills, as with all modelling pursuits :-)

[Subculture]

Seems to be a rather large difference in price. Fusion 360 is free to hobbyists, but Rhino isn't AFAIK.

[QuarterMaster]

Thanks guys!

I will be going with Rhino for design software. One of my engineers recommends it highly, and Fusion360 is not doing it for me.

How about some specifics regarding this decision, aside from the ME's(?) recommendation. Pro's, cons?

[Thorbrandr]

Thanks guys!

I have a UB1 in 1/30 almost printed in ASA. Currently reprinting a few hull sections where the slicer supports caused some issues. In the process I changed over to a Micro Swiss direct drive on my Ender 6. That made a HUGE improvement with the ASA. Between that and tweaking slicer settings, it prints ASA better than PLA now.

I am using 100% fill on this model. Don't want to risk water incursion into the hull walls and support rings.

I will be going with Rhino for design software. One of my engineers recommends it highly, and Fusion360 is not doing it for me. Now to settle on 1/35 or 1/32 for the U-35 model I want to build and start designing. I will probably go with 3 mm for the externals. The UB1 model print has been a useful learning exercise for some of the details. That model is well laid out, but there were some issues with getting the auto generated supports to play well.

[Sinksalot]

For my subs I print with ASA or ABS, 3 to 4mm thick. For subs I print with resin, 2 to 3mm due to how heavy the hull would be if you make the hull to thick using resin.

[rwtdiver]

There is another way to adjust wall thickness, but only if the files you're using are not hollowed, IE: you have a solid model of a submarine with no internal void. In that case, you can adjust wall thickness via the slicer settings. Typically this is a variable known as "perimeters". You set the infill at 0% and then set the perimeters at something like 7. This gives you a hollow part that you can adjust hull thickness on by simply increasing the number of perimeters.

Again, this does not work if you have a hollow part already. Adjusting the settings as I mentioned above will simply make the walls of the boat hollow, not adjust the wall thickness itself.


Bob

Hi Bob,

I am already at a point of no return on this build. I will finish it out as is! But I will defiantly try what you have suggested. This 36" long Ictineo boat will certainly be robust to say the least!



Thanks for your suggestion. :-))

Steve Hodges would sure appreciate the wall thickness! :-)) 34" Boat and I am into my 2nd roll of PLA (Most likely finish out to 3.5 rolls of PLA)

Rob
"Firemen can stand the heat"

[RCSubGuy]

There is another way to adjust wall thickness, but only if the files you're using are not hollowed, IE: you have a solid model of a submarine with no internal void. In that case, you can adjust wall thickness via the slicer settings. Typically this is a variable known as "perimeters". You set the infill at 0% and then set the perimeters at something like 7. This gives you a hollow part that you can adjust hull thickness on by simply increasing the number of perimeters.

Again, this does not work if you have a hollow part already. Adjusting the settings as I mentioned above will simply make the walls of the boat hollow, not adjust the wall thickness itself.


Bob

[rwtdiver]

Thank you CC!

The process you describe sounds above my skill levels! I already have 4 of the hull sections printed so I will just go ahead and finish this project out the way that it is. I am kind of at that point of no return. Lesson learned again! Build the project as per design! :-))

Thanks again for your help and suggestion CC, I appreciate you taking the time to post it up!

Rob
"Firemen can stand the heat"

[CC Clarke]

The hull thickness is determined by the STL file. A slicer cannot change the geometry an object (yet).

Without the original CAD file, to change the hull thickness, the STL file has to be opened and repaired inside a dedicated modeling program.

One of the many ways to change the thickness of the original object is:

Subtract an object that follows the interior contour of the hull, and is 2.5 mm larger than the original mesh.

Select, cut and paste the polygons of the interior mesh into another layer.
Extrude the mesh 2.5 mm outward.
Flip the poly normals of the inside faces and extrude them inward just enough to be slightly larger than the original interior.
Stretch the ends (the X Y Z axis depends on your object’s orientation) to exceed the original mesh length.
Subtract the slightly larger (2.5mm) cutting tool from the original mesh to remove 2.5 mm from the interior.

In a perfect scenario, you would have the file in the original CAD format, go back in the timeline to the point where the hull thickness was created and just edit the desired thickness.

5mm is pretty thick!

CC