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Beginner Question on building a shape in Houdini

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bobbyfunkhouse
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Hi All,

I've just begun my venture into Houdini, and am keen to start off with a bit of modelling.

My background is 19 yrs NURBS surface modelling in Rhino 3D and am looking to learn Houdini for both modelling and it's simulation capabilities.

In this case, I'll be looking to rebuild this part (attached and pictured) in Houdini and then aim to morph/melt the shape I've built.

The shape I'm trying to build is a simple revolve with some 'boolean grooves' (great name for a band) which are radially arrayed.

I am asking where is the best place to start in terms of learning to build this geometry? Any pointers would be greatly appreciated or if anyone is willing to show me that would also be great; I'd be happy to do a skill exchange too if you're keen to learn more about Rhino?

Cheers,

Bob

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Edited by bobbyfunkhouse - Feb. 3, 2026 14:33:49

Attachments:
shape_1.obj (14.5 MB)
20260203_houdini_howtobuild_bob_001.jpg (104.3 KB)
20260203_houdini_howtobuild_bob_002.jpg (62.0 KB)
20260203_houdini_howtobuild_bob_003.jpg (135.1 KB)

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Konstantin Magnus
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Hi Bob,

you will find an example attached. Look onto my website for more modeling examples.

Attachments:
boole.hip (127.4 KB)

https://procegen.konstantinmagnus.de/ [procegen.konstantinmagnus.de]
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bobbyfunkhouse
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Thanks so much Konstantin, Had a good look at your website, this is a great resource. I especially like the PBR fire hydrants shorts.

Bob
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bobbyfunkhouse
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Hi Konstantin,

I took your file and had a go at adding some polybevels and also animated the circle uniform scale value (from frame 0 to 180) so the tubes kind of press into into the main cylinder (this will be my aim later on when I animate it, as if it is a molten glass vial being formed).

I tried to add a polybevel after the boolean node to soften it all up, but the result was quite coarse where the tubes intersect with the main cylinder.

Is there a way/node to neaten up the topology of both parts (tubes and main cylinder) at these intersections to create a consistent nice radius when the tube push into the main cylinder body?

Thanks.

Bob
Edited by bobbyfunkhouse - Feb. 3, 2026 17:16:51

Attachments:
bob_1.hipnc (147.7 KB)
20260203_houdini_howtobuild_bob_005.jpg (177.3 KB)
20260203_houdini_howtobuild_bob_004.jpg (382.5 KB)

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Konstantin Magnus
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When working with meshes you would rather use subdivisions for smoothness.

Attachments:
grooves.hip (81.2 KB)

https://procegen.konstantinmagnus.de/ [procegen.konstantinmagnus.de]
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bobbyfunkhouse
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Thanks again Konstantin,

This certainly seems a much cleaner way of doing it, however you seem to lose some of the arch definition at the top of the indent. But maybe this is me being too perfectionist; after all a glass moulded form would never be this controlled unless the details were cut in after I guess.

I tried to add some control by selecting the internal edges and then adding a polybevel node before the subdivision and this worked to some degree but unsure if the final result is still acceptable in terms of a clean topology going forward?

Thanks,

Bob

Attachments:
bob_2.hipnc (94.3 KB)
20260203_houdini_howtobuild_bob_006.jpg (124.2 KB)
20260203_houdini_howtobuild_bob_007.jpg (246.0 KB)
20260203_houdini_howtobuild_bob_008.jpg (340.9 KB)

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Mike_A
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When I saw your first post I thought 'Just wait until Bob gets to the bevelling...' : )

It's not a Houdini issue as such, just the nature of polygon based modelling vs NURBS. With NURBS you've got the precision and relative ease of bevelling etc - but at the cost of requiring a more structured and precision approach. Polys allow that push, pull, deform freedom, but at the cost of frequently requiring some careful construction planning or topology wrangling to make things like bevels work.

I think you'll find that if you're going to melt / morph this, the more formal style of polygon topology - all neat quads etc - can often take a back seat as Houdini will often be using a triangulated mesh, or VDB volumes for simulation processes. So, I wouldn't sweat the topology at this stage.
Edited by Mike_A - Feb. 5, 2026 16:37:54
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Konstantin Magnus
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You could extrude the grooves inwards and round them by their distance and direction to their centerline.

Edited by Konstantin Magnus - Feb. 15, 2026 05:55:06

Attachments:
grooves_arc.png (913.8 KB)
grooves.hip (144.5 KB)

https://procegen.konstantinmagnus.de/ [procegen.konstantinmagnus.de]
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Konstantin Magnus
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Quick demo including bevels.

Attachments:
grooves_00.mp4 (797.4 KB)
grooves.hip (145.8 KB)

https://procegen.konstantinmagnus.de/ [procegen.konstantinmagnus.de]
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