How to transform only specific points of a mesh

[Eugen]

Hi!
What’s the component to ‘filter’ and work only on a subset of vertices of a polygon mesh?
I’d like to scale only part of the mesh, without creating a second mesh. The list of vertex IDs I have.

I’d know how to write a Python component for that, but better ask before…

Thanks!!
Best regards
Eugen

[RIL (Rolf)]

Mesh Difference, Mesh Intersection? (if you create temp meshes to intersect with) :

You can also make (Brep) Boxes, Spheres etc, and place them in the region of the points you want and perform a Point Inclusion test.

If you have an existing mesh you can use DeconstructMesh->Vertices to the points to start from and to filter as described above.

// Rolf

[Eugen]

Hello!
The part of the mesh I want to work on cannot simply be surrounded by any simple shape.

But I think I get the idea now…
‘DeconstructMesh’ > split the vertex list into a part that will be transformed and a part that remains using ‘Sub List’ > combine the 2 vertex lists again > ConstructMesh

However, I think I’ll better do this with a few lines of Python code.

Thanks!!
Best regards
Eugen

[RIL (Rolf)]

@Eugen

any simple shape

if it’s not a free form shape you can bundle a whole bunch of Breps (and evaluate Point Inclusion for every each one of them…) to cover the shape/part you want to “capture” from the original mesh.

Happy coding!

// Rolf

[Eugen]

I see!
Thanks again! =)

[RIL (Rolf)]

Hint about a thead on point inclusion (if the inbuilt shapes are too slow). Read the entire thread. Super fast stuff.

Super-super fast Point Inclusion test for Cylinder/Breps?

I generate the cylinder from the two tilted (input) end points C, H defining the cylinder axis + (input) radius R. Now I have implemented the ClosestParameter concept in my components, and the result is just awesome. Mesh deconstruct 15 ms (46.000+ vertices) Filtered for (tilted) Cylinder Inclusion in 20 ms (and less) [image] Fig.2 … and the filtered result : [image] Absolutely perfect! Now we are talking business. Wow! // Rolf

Super-super fast Point Inclusion test for Cylinder/Breps?

I don’t know what difference it makes, but in my case I tried transforming a subset of a “deconstructed” mesh, like so Fig.1. GH def [image] Fig. 2. Mesh with a “flat cylinder” inside (barely visible) and the red points are filtered as being “inside” a BoundingBox of the cylinder. Next step to filter points inside the (leaning) cylinder. [image] But the above steps could be skipped altogether if I could only transform the disc (cylinder) together with the mesh points (around the center o…

// Rolf

[AndersDeleuran]

You can access the vertices of a mesh and set a vertex like so in RhinoCommon using GHPython (note that this method has three other overloads i.e. different signatures/ways of setting the vertex). Make sure to pass your mesh to the GHPython component as a Mesh (right-click component -> Type Hint -> Mesh) to directly access the vertices using the dot notation syntax i.e. MyMesh.Vertices.SetVertex(indexOfVertex, newPosition)

[Eugen]

Got it, thanks a lot everyone!!

Some things are simpler in code indeed… (I came to love Python here! =)

[giacomo_forcina (Giaco)]

@AndersDeleuran Hello, I wanted to follow the example you posted there, but unfortunately the links are broken.

Could you address me to the original page?

Thanks in advance!

[AndersDeleuran]

Sure, there you go:

https://developer.rhino3d.com/5/api/RhinoCommonWin/html/T_Rhino_Geometry_Mesh.htm

https://developer.rhino3d.com/5/api/RhinoCommonWin/html/P_Rhino_Geometry_Mesh_Vertices.htm

https://developer.rhino3d.com/5/api/RhinoCommonWin/html/T_Rhino_Geometry_Collections_MeshVertexList.htm

And then calling one of the SetVertex() methods of the MeshVertexList.