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Summary
After grasping the basics of creating a mesh using Vertices and Faces, it is important to understand some techniques for generating them using more efficient processes. This page walks through some code for plotting a mesh from mathematical equations. Along the way, you can see how Vertices and Faces are organized using variables and loops.
Wave Surface
Variables
These variables are both essential to creating the wave surface as well as giving us control over creating variations.
# mesh arrays verts = [] # the vertex array faces = [] # the face array # mesh variables numX = 10 # number of quadrants in the x direction numY = 10 # number of quadrants in the y direction # wave variables freq = 1 # the wave frequency amp = 1 # the wave amplitude scale = 1 #the scale of the mesh
Vertex Array
With the variables defined, we can use them to control the parametric equation for a Wave surface. The wave surface is defined with the parametric form:
- x = i
- y = j
- z = Cos(i) + Sin(j)
To control the surface, we can use our defined variables for scale, frequency and amplitude:
- x = Scale * i
- y = Scale * j
- z = Scale * (Amplitude*Cos(i * Frequency) + Amplitude*Sin(j * Frequency))
By placing x, y, and z variables in to a nested For loop with variables i and j, we can plot a grid of vertices which map the parametric surface.
At this stage, we can verify the how the points are plotted by creating our mesh with the vertex array and an empty face array.
#fill verts array for i in range (0, numX): for j in range(0,numY): x = scale * i y = scale * j z = scale*((amp*math.cos(i*freq))+(amp*math.sin(j*freq))) vert = (x,y,z) verts.append(vert) #create mesh and object mesh = bpy.data.meshes.new("wave") object = bpy.data.objects.new("wave",mesh) #set mesh location object.location = bpy.context.scene.cursor_location bpy.context.scene.objects.link(object) #create mesh from python data mesh.from_pydata(verts,[],faces) mesh.update(calc_edges=True)
Face Array
After filling out the vertex array, we need to fill the Face array. Each item in the face array should contain 4 indices that refers to an item in the vertices array.
#fill faces array count = 0 for i in range (0, numY *(numX-1)): if count < numY-1: A = i # the first vertex B = i+1 # the second vertex C = (i+numY)+1 # the third vertex D = (i+numY) # the fourth vertex face = (A,B,C,D) faces.append(face) count = count + 1 else: count = 0
Final Code
import bpy import math # mesh arrays verts = [] faces = [] # mesh variables numX = 10 numY = 10 # wave variables freq = 1 amp = 1 scale = 1 #fill verts array for i in range (0, numX): for j in range(0,numY): x = scale * i y = scale * j z = scale*((amp*math.cos(i*freq))+(amp*math.sin(j*freq))) vert = (x,y,z) verts.append(vert) #fill faces array count = 0 for i in range (0, numY *(numX-1)): if count < numY-1: A = i B = i+1 C = (i+numY)+1 D = (i+numY) face = (A,B,C,D) faces.append(face) count = count + 1 else: count = 0 #create mesh and object mesh = bpy.data.meshes.new("wave") object = bpy.data.objects.new("wave",mesh) #set mesh location object.location = bpy.context.scene.cursor_location bpy.context.scene.objects.link(object) #create mesh from python data mesh.from_pydata(verts,[],faces) mesh.update(calc_edges=True)
