Ripple/Contour Effect-How?

Hello Forum, I have a slightly different challenge than my usual ones. We have received some models from an artist, they will be large stone benches and feature pieces. On 2 of them we need to have a slightly contoured/ripple effect on the side faces, photo attached of something similar. We received scale wooden models which have been scanned, now they want 2 of them with this slight ripple effect, bands 150 apart, 20-30 deep. Sample file attached. What would be the best method/workflow to apply this to the 2 models ? @pascal @theoutside maybe have some tips on this, or anyone who has done something similar ? tia
(ps I’m not familiar with GH)

Contour Ripple To Sides.3dm (1.6 MB)
(edit-extra image added)

This is a very regular fairly geometric shape which is much easier to model as nurbs surfaces instead of subD.
All you need are the border curves of the upper and lower conter and a profile curve of the zigzag grooves.
You then do a 2-rail-sweeps using the border curves asrails and the zigzag curve as profile.

something like this:

Another way would be: Take the existing surface and create an offset surface with the appropriate distance (height of the ripples/zigzags you want to create). Then create horizontal surfaces at the positions of ripple/zigzag lines and intersect with original and offset surfaces to create surface lines.
Then use these lines either to do sweeps or lofts.

Like this (took roughly 5 mins):

Contour Ripple To Sides-ng-2.3dm (5.7 MB)

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@norbert_geelen thanks for your suggestions Norbert, much appreciated. I’ll try your methods :+1:t4:. I’d love to hear if anyone else has another approach, always good to learn different workflows :blush:

Hi @norbert_geelen how did you keep the top surface and the ripple sides as one. I get what you mean with both methods, as in getting the contours or duplicating the edges of the top and bottom surfaces etc it’s just that top surface I’m struggling with ? tia for your help with this

I overbuild the rippled side surfaces using the untrimmed original side surface (and the derived offsetsurface. After that I extracted the 3 main surfaces on the top and the one on the bottom, untrimmed them and retrimmed these with the rippled sidesurfaces to get the final closed polysurface.

when you say overbuilt, you mean made the object taller ?

Yes, I build the rippled surface at the height of the untrimmed side surface of your original (nurbs) object.
Just make sur you go further then the top surfaces.

you can also fade them in and out by adding straighter or more “rippley” section curves along the rails.

Do it with history enabled and you can iterate by pulling points on the curves with the surface and play with how much wavy-ness and how much fade you get.

it helps if you rails have matching point counts , and your profile curves have matching point counts (even the straight sections) rails and profiles do not have to have matching point counts to each other.

I’m sure there is a clever way to grasshopper this, however I’m but a simple cave man…

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yeh same here with GH, its a new detail to me for the kind of large granite blocks we shape and fabricate, so struggling a little with it :man_shrugging:t4:

history will be your friend here. You can set it up and then iterate all day…