I have created a hull surface with 2 creases in it (I’m also using ORCA) .
These creases have suddenly appeared rounded - See attached jpegs.
The ORCA sections show the surface as designed, however the surface itself is different.
This happened without any action on my part - is there a preference setting issue?
As can be seen by the buttock sections, the crease at the stern has rounded out (On the surface) while the sections show a crisp crease
any feedback/suggestions are welcomed
tom
That looks like the render mesh that is displaying the rounded chine aft. Look at the section and buttock lines generated and you can see that the hard chine is still there. Maybe increase the density of your display and render mesh and see if that preserves the chine crispness. Nice hullform with a surprisingly economical control point mesh that is very clean. Are you stacking control points to form that fading chine? You may be creating a ‘degenerate surface’ by doing so, but don’t fret about that. I got very offended when a guy here used that term on a hull surface that I had posted, took it personally as ‘degenerate’ has negative connotations. He was far more experienced with singularities and that sort of thing and when I stopped feeling hurt and paid attention to what he was saying that helped me a lot. Also are you using ‘CP point weighting’? Could you post the hull with net turned on without the rub rail, caprail and rub strake so I can see the CP’s better. Is that a Pacific Northwest trawler hull form? Looks like something out of NATIONAL FISHERMAN, the publication that got me interested in marine design when I was just a kid. Nice work for sure.
Did you use MergeSrf to merge surfaces together? If so depending on the particular settings used the kink will be rounded. Smooth=Yes and Round > 0 results in rounding of the kink.
Did you use NetworkSrf to create the surface? If so NetworkSrf always results in a surface without kinks, even when one or more input curves have kinks.
Update: Given the few number of control points my guess is @jodyc111 is correct: the rounding is caused by softening applied to the render mesh, not the NURBS surface.
Look at the model in Wireframe view mode. Is the rounding still there?
Yeah that looks like the mesh just isn’t capturing that well, not that there’s anything per se “wrong” with the actual surface. Increasing the Density or reducing the “Max dist edge to surface” might do it. Sometimes running Reparameterize with the Automatic option also helps with meshing on point-edited surfaces.
Jody:
Wow Awesome that the response is so quick!
I played with the mesh density (now set to 1). and manipulated a few points gently to obtain the desired crispness & blend. A few extra jpegs are attached wihich will show how my control points are placed. I tend to try to make do with as few points as possible while getting the desired result (shape).
I’m not a numbers chaser but try to make sure that the hullform isnt a type outlier - it fits in place.
The influences are definitely there from the Pacific Northwest ( I am very fond of William Garden’s work).
As mentioned; attached are a few more jpegs - ignore the arrangement beneath -its from an earlier work.
hopefully this will rectify my issues - though any other comments are welcome…
Regards,
tom
Hi David;
I used 1 surface, after creating sheer and fairbody curves and a midship section . From there i added control points and the two kinks, and trimmed the surface at the sheer for the “Break”.
it seems that changing the surface mesh density (and a few subtle point movements) resolved my troubles - interesting that it is the 1st time I’ve had that issue.
Thank you for your comments
tom
Hi Jim;
I haven’t played with those particular options - maybe I’ll “Save As” another file and play with them - you can never know too much
Thanks for your comments.
tom
Such a nice effort. Can I ask what the purpose of your model is? Going to build that? I particularly like how you have modeled the deadwood and the intersection with the aft corner of the keel will form a nice ‘rabbet’ in much the same manner of actual wooden construction.
Jim, wasn’t it you that enlightened me to the ‘degenerate surface’ a few years ago? How does the kink command avoid stacking control points. MaxSurf loved stacking points for chines but that raised hell when imported to Rhino, sometimes couldn’t even generate hull lines because of that.
Tom are you using Orca3D? You are doing some serious marine design work there and while expensive, Orca3D is worth it if going much further. Keep us posted!
Jody
Kink command inserts a full multi-knot. The fundamental difference between stacked control points and a control point at a multi-knot is each of the stacked control points has a unique parameter value while the multi-knot control point has a single parameter value which is repeated. The algorithms for curves and surfaces are (or should be) able to deal with multi-knots.
Hi Jody:
These efforts are for the most part for “Yucks & Chuckles”.
I apprenticed as a boatbuilder in the early '80s and worked as such for almost 20 years before other commitments took precedent. In 2018 I went to the The Landing School for Marine Systems and Yacht Design ( My Introduction to Rhino!) - kind of a bucket list thing to do…
I typically create use cases for designs; in this case a trawler yacht with Pacific North-West influences, that can remain independent for extended periods. The design needs to recognize an increase in demand for creature comforts and consider the possibility of alternative propulsion systems (hybrid/diesel electric) though as drawn I’ll start with a modern diesel & genset ( although its tempting to put a Gardner in it)
Lastly; The design is meant to help provide a working example for an excel workbook which specifies many/most of the physical requirements of such a boat (In so far as I want to take a “Spec” or prelim design that’s at the very start of the design spiral.)
Its good fun - and though I have put a portfolio out on the web (tomsboatshed.com - shameless plug)
I’m under no illusion about making money at it - there are a lot of folks out there doing much the same - smarter than me…
I appreciate the valuable feedback. For my experience Rhino - and Orca - have been (are) excellent products with great support - almost as much fun as carving a half hull!
Note: attached is the keel - Rabbet included!
tom
Oh! I had a look at your web portfolio years ago, nice stuff. You lost me at Excel workbook though…
I need to refocus on my Rhino3D marine design, I have gotten sidetracked lately by all the lightspeed development of AI imaging. Not a bad thing to try and get up to speed on but a ways to go before it can really be relied upon within the realm of 3D design and modeling, at least for marine design. But here is a peapod of sorts I conjoured up based on a rowing peapod that I did for Bob Perry a few years ago. Just an AI render but came out with a bit more sheer at the bow than I intended. Promising though.
Jody;
The excel workbook is used for specification/engineering calculations - Material properties & Scantlings, Power requirements, prop size, shaft size etc, and, although Orca does provide a material/weight analysis function It’s a good idea to put this in the spreadsheet too - to help with ballast & trim.
It is pretty dry stuff compared to a nice render, but really cool when things resolve / Reconcile the way your eyeball wants them to.