How to convert polysurface to surface , and than to make a pattern on it

Hi , I would like to your help…
I’m looking to do a swimear in grasshopper .
My first geometry was mesh so I convert it into a polysurface, but I would like to convert it to one surface and chose part of the points to make a pattern by attractor.
maybe you have some advise … I would like to hear .


you cannot convert mesh geometry into good nurbs surface models. Furthermore its close to impossible to do serious free-form surface modelling in native gh. Representing such a shape with one surface patch? Well even another ambitious aim. Lets say it like this: You can create patterns on meshes or on multiple surfaces and you can model such shapes in Nurbs with Rhino and create patterns on it. None of these tasks are easy, universal and fast to solve. Excuse me for being so generic, but your questions are like this as well. Hope this still helps you.

Hi Tom, thank you for your answer!
I would like use the vectors from the mesh but not with all the vectors, only numbers of vectors … How I can choose specific vectors from the mesh shape in this case?

you can access mesh properties with components found in the mesh tab. usually you access vertices, and normals by index or closest point algorithm, but you can also filter by some sort of inclusion testing, for instance by defining an selection geometry and checking for those members being inside that selection geometry. On tueday, i can give you an example, because I’m not having access to Rhino now. You can also make a new thread with this question and maybe someone else gives you an example. Also check the old grasshopper3d forum for examples. There you can download tutorial pdfs as well and you can also check out youtube videos about mesh editing in gh. Furthermore I can always advise you to learn basic scripting, something which actually simplifies working with meshes within the gh environment. In addition to that, there is a „math for designer“ pdf on the old grasshopper webpage. Vectormath is not difficult but if you truly understand, it will be much easier to understand definitions and scripts and solving your problems. Take time and practise, gh is easy to work with but very hard to master. Its visual programming nothing more, nothing less.

Have I a nice weekend.