As you can see in the video, I have a very clean network surface. But when I use FlowAlongSurface it becomes very dense, which is a big disadvantage for FlowAlongSrf. Cand this be improved or avoided? (I cannot PreserveStructure=Yes in this case, because my edges won’t match) FlowAlongSrf No Pre…

Time is not a good metric. It would make the result different on different devices. Did you try lowering the document tolerance and flow both with preserve=no?

[image] Bogdan_Chipara: The geometry will land exacatly into place and it will also preserve structure. Your thinking that will result in a perfect with with the target surface is simply wrong, that’s not how the math works.

Of curse it will. It will preserve the structure of the isocurves and land exactly into place. It’s a combination between PreserveStructure=Yes (keeps same iso) and PreserveStructure=No (edges land into place)

[image] Bogdan_Chipara: Of curse it will. It will preserve the structure of the isocurves and land exactly into place. No, if it did there would be no reason for this “PreserveStructure” option in the first place. For one example, it is literally impossible to match up one surface edge to a…

I disagree. It should be possible just like CageEdit does the transform. If it’s possible with CageEdit it should be possible with FlowAlongSrf.

[image] Bogdan_Chipara: I disagree. It should be possible just like CageEdit does the transform. If it’s possible with CageEdit it should be possible with FlowAlongSrf. You are entirely mistaken that CageEdit can do some special magic that FlowAlongSrf can’t. Again, why does this option exi…

[image] Bogdan_Chipara: @JimCarruthers , you’re totally not convincing. Look, FlowAlongCurve does it also. You are making no sense and not listening. I’m done with you and your GPT slop no one cares about.

Oh, thank you very much for staying away from my posts Jim.

What you are showing for meshes, does not apply. Meshes are not further refined, so PreserveStructure yes/no doesn’t matter. When you transform the green surface with preserve = no and the black with preserve=yes, the resulting edges are close in deviation (0.454 vs .486): [image]

If you model it a bit more carefully and give the black surfaces an extra set of knots to work with you can get into file tolerance: [image]

FlowAlongSrf PreserveStructure=No - very dense result - why?

Rhino Rhino for Windows

Bogdan_Chipara January 17, 2026, 4:42pm 11

@JimCarruthers , you’re totally not convincing.
Look, FlowAlongCurve does it also.

“Again, why does this option exist if you think it’s not needed?” - not saying is not needed!
I am arguing for another mode. Preserve, yes, no should stay as they are and implement something extra.

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FlowAlongSrf PreserveStructure=No - very dense result - why?

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