[Modeling] Y-junction of freeform shape

hello all,

for a while now, i have been struggling with a private project (every couple of months i give it another go, since 2 years now! hoping I’ve improved my rhino skills enough. :see_no_evil: ).
i just don’t have the slightest idea of how to solve this one. It’s driving me insane.

attached i tried to sum up the approaches (A-E) i tried. but the center of the junction always got me in trouble and blendsurface, sweeps, patches etc always produced messed up surfaces. (the latest according this tip by @Lagom in this thread )

any hint on what i am doing wrong would be appreciated. :raised_hands:


HexagonRoof_1.0.3dm (2.3 MB)

If precision is not your top priority, the easiest and cheapest way to do it is using Rhino 7 SubD commands.

introduction to SubD in Rhino 7 WIP: https://vimeo.com/360579837

Otherwise, you can purchase XNurbs Rhino plugin ($350) and use its multiblend command. You can purchase it here: https://www.xnurbs.com/purchase/

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looks if this video is helping you

is a bit long and overelaborated but it’s exactly the Y branch construction.

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@andrew.nowicki thanks for the hint! forgot about checking out the SubD function 7 WIP. I am still determined to have a “correct” construction of the junction, though. Improving freeform skills and all. :wink: but i definitely have to get familiar with SubD.

@skysurfer thanks for the video. looks like an interesting construction indeed. i’ll check it out. although quickly going through it, it also seems to be based on circular endshapes (like in the video i posted), which is not the case for my object? anyway, I’ll give it a go.

just a quick update…

@andrew.nowicki thanks again for the hint! Finally found the time to play with the SubD function in the current WIP… this is amazing. I have to be careful not wanting to do all my modelling with SubD from now on. :monkey: (Would car designers be happy with the surface quality, though? Asking for a friend.)

Espacially the video below was very helpful for me to get an overview of what subd can do. Highly recommended for beginners, I guess.

But the quest to the perfect junction remains unsolved for now. Maybe in a couple of months I give it another go with some old school nurbs modelling. :slight_smile: (By turning the subd surface back into nurbs, I got a better feeling of how I should have constructed it.)

11 years ago Brian James made this Y-branch polysurface using Rhino 4: https://vimeo.com/3297459


Yes, found many tutorials and examples for y junctions. But they just wouldnt work in my case, i felt.
With subd it took me 15minutes. :slight_smile:
… and possibly provided me with a hint of what i was doing wrong.

but u r right, it’s most likely not the most difficult modelling job in the world. Unless u r someone like me with a skillset just above basic. :see_no_evil: