Generate parameterized uniformly distributed holes on the STL surface

[WHUT666]

I want to make Engraving Patterns on Thin_Shells. Starting from the stl surface, I first calculate the normal direction and center of each patch on the stl surface, then use the patch center and normal phase to build a cylinder, and finally obtain the Engraving Patterns through Boolean operations, and then obtain the thin shell through surface offset. How should I implement this through python, especially parameterized holes?

[Grantim]

Hello!
Could you please provide stl files and/or some images of input and output you are willing to achieve?

[WHUT666]

Thank you very much for your reply，I use this stl file ，I want to achieve something like this.

pig.zip

[WHUT666]

I want to use it to reduce the material loss of 3D printed thin shells. I got inspiration from this paper, but I don’t need as complicated functions as in the paper. I just want to achieve a circular pattern.
A_Parametric_Design_Method_for_Engraving_Patterns_on_Thin_Shells.pdf

[Grantim]

This script may work for you:
Input Mesh

Fixed and thicken mesh

Cylinders

Result

from meshlib import mrmeshpy as mm

path = "working_directory"

# load mesh
mesh = mm.loadMesh(path + "pig.stl")
box = mesh.computeBoundingBox()
thickness = box.diagonal()*1e-2

# heal mesh (your mesh has self-intersectoins and not connected parts)
goParams = mm.GeneralOffsetParameters()
goParams.signDetectionMode = mm.SignDetectionMode.HoleWindingRule
mesh = mm.generalOffsetMesh(mesh,0,goParams)

# sample point
points = mm.meshToPointCloud(mesh)
sampleDistance = thickness*2
samples = mm.pointUniformSampling(points,sampleDistance)

# thicken mesh
mesh = mm.thickenMesh(mesh,-thickness)
ds = mm.DecimateSettings()
ds.maxDeletedFaces = 10000000
ds.maxDeletedVertices = 10000000
ds.packMesh = True
ds.maxError = thickness * 1e-1
mm.decimateMesh(mesh,ds)
mm.saveMesh(mesh, path+"thickPig.stl")

# create cylinders from samples
meshes = []
cylinders = mm.vectorConstMeshPtr()
cylinders.resize(samples.count())
for i in range(samples.size()):
    if not samples.test(mm.VertId(i)):
        continue
    pos = points.points.vec[i]
    norm = points.normals.vec[i]

    meshes.append( mm.makeCylinder(sampleDistance*0.4,2*thickness,16) )
    xf = mm.AffineXf3f.translation(pos + 0.5*thickness*norm) * mm.AffineXf3f.linear(mm.Matrix3f.rotation(mm.Vector3f(0,0,1),-norm))
    meshes[len(meshes)-1].transform(xf)
    cylinders[len(meshes)-1] = meshes[len(meshes)-1]

# unite all cylinders into one mesh
cylinderesMesh = mm.uniteManyMeshes(cylinders)
mm.saveMesh(cylinderesMesh, path+"cylinderesMesh.stl")

# engrave
resMesh = mm.boolean(mesh,cylinderesMesh,mm.BooleanOperation.DifferenceAB).mesh
mm.saveMesh(resMesh, path+"resMesh.stl")

[WHUT666]

Thank you very much for your help！！！