如何使用 python 在 Blender 2.9 中将材质的基色设置为等于顶点颜色？

Question

这就是我实例化网格 object 和材料的方式：

mymesh = bpy.data.meshes.new(objname)
myobject = bpy.data.objects.new(objname, mymesh)
mymat = bpy.data.materials.get("Material")
if mymat is None:
    mymat = bpy.data.materials.new(name="Material")
if myobject.data.materials:
    # assign to 1st material slot
    myobject.data.materials[0] = mymat
else:
    # no slots
    myobject.data.materials.append(mymat)

下面是我如何设置顶点 colors 的颜色：

if len(mymesh.vertex_colors) == 0:
    mymesh.vertex_colors.new()
    
for f in mymesh.vertex_colors[0].data:
    f.color = rgb # (0,0,0,1) for black

当我处于顶点绘制模式时，我可以看到 colors，但是当我使用 Eevee 或 Cycles 渲染场景时，colors 不显示。

我可以通过使用 UI 将材质的基色更改为等于顶点 Colors 来解决此问题，但是如何使用 python 代码来做到这一点？

编辑：也许解决方案使用bpy.data.materials["Material"].node_tree.nodes["Principled BSDF"].inputs ？

Answer 1

我想做类似的事情。 我不知道您是否仍在研究它，但这是我发现的似乎适用于 Blender 2.92.0 的解决方案。

要测试脚本：

• 创建一个新的立方体（命名为“Cube”，默认是这种情况）
• 将脚本导入Blender中的脚本window
• 点击“跑”

import bpy
from random import *

# ---------- SET RANDOM COLORS TO VERTICES ----------

# Load vertex colors data
mesh = bpy.data.objects["Cube"].data
if not mesh.vertex_colors:
    mesh.vertex_colors.new()
    print("Object had no vertex colors, adding them")

# Assign random colors to vertices
for vCol in mesh.vertex_colors[0].data:
    for i in range(len(vCol.color) - 1):
        vCol.color[i] = random()
        
# ---------- LOAD AND LINK MATERIAL TO MESH ----------

# Load material
mymat = bpy.data.materials.get("mymat")
if mymat is None:
    mymat = bpy.data.materials.new(name = "mymat")
    
mymat.use_nodes = True
    
# Link material to mesh
if mesh.materials:
    mesh.materials[0] = mymat
else:
    mesh.materials.append(mymat)
    

# ---------- MANAGE NODES OF SHADER EDITOR ----------

# Get node tree from the material
nodes = mymat.node_tree.nodes
principled_bsdf_node = nodes.get("Principled BSDF")

# Get Vertex Color Node, create it if it does not exist in the current node tree
vertex_color_node = None
if not "VERTEX_COLOR" in [node.type for node in nodes]:
    vertex_color_node = nodes.new(type = "ShaderNodeVertexColor")
else:
    vertex_color_node = nodes.get("Vertex Color")

# Set the vertex_color layer we created at the beginning as input
vertex_color_node.layer_name = "Col"

# Link Vertex Color Node "Color" output to Principled BSDF Node "Base Color" input
links = mymat.node_tree.links
link = links.new(vertex_color_node.outputs[0], principled_bsdf_node.inputs[0])

以下是一些帮助我做到这一点的资源：

• https://docs.blender.org/api/current/bpy.types.NodeLink.html?highlight=nodelink#bpy.types.NodeLink
• https://docs.blender.org/api/current/bpy.types.ShaderNode.html
• https://docs.blender.org/api/current/bpy.types.MeshLoopColor.html
• https://blender.stackexchange.com/questions/23436/control-cycles-eevee-material-nodes-and-material-properties-using-python