MoI discussion forum > Smooth sweeps?

From:

15 Sep 2006 (1 of 7)

115.1
I drew in a set of hull lines from a boat plan, tonight. Used them to perform a sweap and basicly it worked ok, except for the undulations visable in the attached pic. I can see how they're being created but not how to overcome it. A lot of tinkering and trying this n that leaves me wishing I could rebuild the surface with control of it's surface divisions. I tried redrawing all my hull lines trying to position the points as uniformally as possable but the pic shows my pitifull result. Looks like a pea pod, not half a boat. It's called loft 4 but thats a typo, it should be sweap 4.
Attachments: hull loft 4.jpg

Post Options

From:

15 Sep 2006 (2 of 7)

115.2 In reply to 115.1
Just speedy test :) Making hull will be better with Loft function :) Ultra basic minima modele :O) I am not sure that this one floats :):):) View top : Delete right part In the other view kill curves generators You have now only surfaces ! Just Show Points and move them as you want :) Of course you can add any points :) You will see that lofts are perfect for clean surfaces generating :) If you see by hasard some artifacts, it's just the rendering view (light shadows) sytem of MoI :) In another way try the fabulous Open Source "Free Ship" http://freeship.sourceforge.net/ And you will can made everything from little boat to Petroleum tanker :) It's like Moi a nurbs Modeler but + Subdivise Surfaces :)
EDITED: 15 Sep 2006 by PILOU
Attachments: hull.3dm hull.jpg

Post Options

From:

15 Sep 2006 (3 of 7)

115.3
Try it with these hull lines. I wind up with undulating points in the loft or sweep. To many to adjust.
Attachments: sections.tga

Post Options

From:

15 Sep 2006 (4 of 7)

115.4 In reply to 115.3
Hehe It's the normal way of naval construction ! Some many lines to join :) You can do that with MoI not now easily now because you can't load the image in background But with these little plug http://home.insightbb.com/~ryanvm/tinyutilities/vitrite/ you can have your window with transparency ! So open your image in one window launch Moi & Bon Courage :) If you want a complet tut for make your boat with a Nurb modeleur go there :) http://www.3drender.com/rhino/boathtml/index.htm Else if you want a naval boat modeler the open source Free Ship is excellent ! http://www.freeship.org/

Post Options

From:

15 Sep 2006 (5 of 7)

115.5 In reply to 115.1
Yeah, these kinds of undulations are frequently a problem when you try to use a larger number of sections. It's annoying because you want to add more sections to create more control, but since the surface is forced to go through each section there is sort of a "ripple" effect that happens. You may try to use a fewer number of sections. Another thing you can try is using loft, with the Loft Style = "Loose" - this will make a surface that is just guided more gently by the cross sections instead of being forced to go right through them, it tends to build a more gentle surface. If you can post the .3dm file, it could help in suggesting some tweaks to make it better. - Michael

Post Options

From:

16 Sep 2006 (6 of 7)

115.6
Michael, Yes, thats exactly the issue. Since the line points vary in position it results in excessive numbers of points in the object, virtually impossable to control manualy. Lofting loosely with the min of stations gives the best result for sure, atm. I notice that re-creating the surface with a uniform simple UV structure is the solution Rhino has taught nurbists to look for. Thinking of adding that in a future iteration? Pilou, Thanks for trying to be helpfull. Yes, obviously, that is the rhino tute I was following. You can see that by the BG image I posted. Yes, the app and transparency combination Michael suggested is very helpfull for the moment. Yes, Freeship is another way to create a hull in obj form. It's much better suited to creating simple planar based hull shapes though and if I resort to another app, why not XSI or Rhino? The exercise was to work through a rhino tute with MoI and thereby improve my nurb-flow and at the same time see what aspects of MoI function were hi-lighted in the process. Cheers Spinner

Post Options

From:

16 Sep 2006 (7 of 7)

115.7 In reply to 115.6
> I notice that re-creating the surface with a uniform simple UV > structure is the solution Rhino has taught nurbists to look for. > Thinking of adding that in a future iteration? I think that you're referring to the Rhino "Rebuild" command. I would like to add this in at some point, but not sure of the schedule for it yet, though. But it kind of seems like a sort of "hack" to use something like this to smooth out results... It would be better if there were smoothing options built directly into the surfacing tool itself in some way. It may be a while before I'll be able to explore that in more detail though (although the "loose" option in loft is one such thing already). - Michael

Post Options