Partial extrusion of subD objects

It is me again with another question regarding subD. The last topic I started was regarding a sink design in rhino using subD, where I showed a few examples of my approach, but I was wrong in all of them.

This time I have a question regarding extrusion of subD.
I will give an example again with a sink.!A3270B8000

I can’t get my head around the geometry around the faucet. Do I model the basin and then extrude the volume underneath the faucet, do I extrude from the base of the sink or the sides.
I have tried a few options but I never get a satisfying result.
Some colleagues are modelling similar objects in Blender, but the methodology in blender is not quite the same as in rhino subd.

Does anyone have suggestions on how the fine tune extrusions of subd (ofc if this is the way to go)?

not seeing anything in your link- can you post an image?

This is the sink I am talking about.

subd all day! I’d do the drain and faucet openings in nurbs after I got the sink the shape I wanted.
(use the right tool for the right job)

sink.3dm (268.7 KB)


Thanks for the file. I am not interested in the model. I am interested in the process. Which section of the subD do you extrude - the base or the sides? How did you join them or split?

I’d be interested to know that too. SubD is clearly super cool and useful, but I think the learning curve seems a little bit ambiguous (not to mention having little to no relation to typical workflows).



not typical for you… yet :wink:

once you start using subd, you will see where and when they are irreplaceable. That said there are plenty of circumstances where they are NOT the right tool. But where they are, they are amazing.

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I totally agree - I’m trying to deep dive but not really getting anywhere yet, past anything blobby. I think it’s a combination of:

  • Wavering about adding too much geometry too soon
  • Trying to ‘imagine’ what the cage needs to look like - entirely dfferent mindset
  • Worrying about toplogy and 3/5 sided stuff etc.

I’m quite blind in respect to ‘good’ SubD etiquette… definitely open to any accepted rulebooks or points of reference!

check out the paper doll hand model I posted. It’s pretty easily digestible and may spark some thought about how to start breaking this stuff down. Imagine if you built your model with post it notes. that is exactly how you’d do it in subd. Make sure you are using box mode for most of your modeling. If your box mode is clean, your subd will be clean.

but most importantly, just make stuff… break it, post it and we’ll sort it together as a community-

i started with a rounded cube, then deleted the top surfaces creating the outside of the bowl-

I then copied and pasted it, and scaled it just a bit to make the inside of the bowl and bridged them together, I inserted points to create the triangle area and moved it up, a little pushing and pulling and you are on your way-

I did 99% of it in box mode, just flopping to smooth to check forms.

More of the same except add the drain

drain_.3dm (353.1 KB)

nice, did you use align to get the circle, or did you just align them carefully by hand?

create a hexagon then align each vertex with each corner by hand

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To create a hole I like to add a subd cylinder, remove the few faces on the target subd, bridge target to cylinder, then remove from cylinder all you don’t need.

Also very nice way to get exact radius of hole/cylinder is to do scale2d.

Useful both for doing hole and pole on subd surface (assuming subd surface to implement on has nice grid)

Nice trick!

The screenshot of the model shows the heptagon.