Python for 3ds max – Mesh manipulation

3ds max 2019

An example of creating a mesh ripple deformation using Python for 3ds max:


Script steps:

  1. Define the effect intensity and a helper point object that will serve as the effect center.
  2. Collapse the object to an Editable-Mesh so its vertices will be accessible by Python.
    Note that the Node‘s Object has to be cast as a TriObject, to access the object’s Mesh data.
  3.  Loop through the Mesh’s vertices, get their world position, and set a new Z position as a sine function of the distance from the effect center.
import math
from MaxPlus import Factory
from MaxPlus import ClassIds
from MaxPlus import INode
from MaxPlus import TriObject
from MaxPlus import Matrix3
from MaxPlus import Point3

# Intensity:
effecr_mult = 1.0

# Effect center:
effector = INode.GetINodeByName('Point001')
effect_pos = effector.GetWorldPosition()

# Prepare object and eccess it's mesh data:
node = INode.GetINodeByName('Teapot001')
new_edit_mesh_mod = Factory.CreateObjectModifier(ClassIds.Edit_Mesh)
node_tm = node.GetWorldTM()
node_pos = node.GetWorldPosition()
obj = node.GetObject()
triobj = TriObject._CastFrom(obj)
mesh = triobj.GetMesh()

# Process the object's vertices:
for i in range(mesh.GetNumVertices()):
     # Get vertex in world space
     vert_pos = mesh.GetVertex(i)
     vert_world_pos = node_tm.VectorTransform(vert_pos)
     vert_world_pos = vert_world_pos + node_pos
     # Get vertex distance from effect center:
     diff_vec = vert_world_pos - effect_pos 
     diff_vec.Z = 0
     dist = diff_vec.GetLength()
     # Set new vertex position:
     mesh.SetVert(i,vert_pos.X,vert_pos.Y,vert_pos.Z + math.sin(dist)*effecr_mult)

* note that when copying and pasting a script from this example, the indentation may not be pasted correctly.

Related Post:
Python for 3ds max – Animated Mesh


3ds max – Use the Particle-Flow Lock/Bond test to have particles move on a surface in

3ds max 2019

The Lock/Bond Particle Flow test can be used to have particle movement restricted to a surface.


This example shows a simple setup in which the particle teapots have a Speed operator set to Random 3D mode that causes them to move in random directions,
While at the same time the Lock/Bond test forces them to ‘stick’ to the surface: