Finding Vertices, Edges, Faces, and Tris using Python

Question

I am trying to access the triangle count of an object with Python. All other python code displays itself when I hover my mouse over the corresponding button in the interface. When I go to the info bar and hover my mouse over the triangle count, nothing appears. When looking in the documentation around data, there doesn't appear to be any clear function to call to get this info.

Answer 1

You can access the polygons of a mesh, then calculate the triangles from the number of vertices per polygon.

import bpy

obj = bpy.context.scene.objects.active
data = obj.data

# FACES, TRIANGLES
total_triangles = 0

for face in data.polygons:
    vertices = face.vertices
    triangles = len(vertices) - 2
    total_triangles += triangles

print(total_triangles)

# VERTICES
vertices = []
for vertex in data.vertices:
    pos = [vertex.co[0], vertex.co[1], vertex.co[2]]
    vertices.append(pos)

print(vertices)

# EDGES
edges = []
for edge in data.edges:
    edges.append([edge.vertices[0], edge.vertices[1]])

print(edges)

Answer 2

Scene statistics. Scene.statistics()

Call Scene.statistics() to get the text shown in the info bar.

Example of from python console, called before and after entering edit mode.

>>> C.scene.statistics()
'v2.79.1 | Verts:24 | Faces:18 | Tris:36 | Objects:3/3 | Lamps:0/0 | Mem:24.70M | Cube.003'

>>> C.scene.statistics()
'v2.79.1 | Verts:8/8 | Edges:12/12 | Faces:6/6 | Tris:12 | Mem:25.35M | Cube.003'

Use string methods to grep out the triangles. Tris:12.

Using Bmesh

The bmesh operator bmesh.ops.triangulate() can be called to, generate and then count the number of triangles.

import bpy
import bmesh

ob = bpy.context.object
me = ob.data

bm = bmesh.new()
bm.from_mesh(me)
stats = ["Faces: %d" % len(bm.faces), 
        "Verts: %d" % len(bm.verts), 
        "Edges: %d" % len(bm.edges)]

# triangulate 
bmesh.ops.triangulate(bm, faces=bm.faces[:])
stats.append("Tris: %d" % len(bm.faces))
print(" | ".join(stats))

#Faces: 6 | Verts: 8 | Edges: 12 | Tris: 12

Or using the method outlined in @doakey3's answer

num_tris = sum(len(f.verts) - 2 for f in bm.faces)

Or via loop triangles (Example)

num_tris = len(bm.calc_loop_triangles())

removing the need to run the triangulate operator.

Similarly for a mesh object

me = context.object.data # mesh object.
me.calc_loop_triangles()
num_tris = len(me.loop_triangles)

Answer 3

import bpy

data = bpy.data.meshes['Плоскость'];
# 'Плоскость' - name of manually selected mesh, for example

# VERTICES
vertices = [];
for _ in data.vertices: vertices.append(list(_.co));

print(vertices);

# EDGES
edges = [];
for _ in data.edges: edges.append(list(_.vertices));

print(edges);

# POLYGONS
polygons=[];
for _ in data.polygons: polygons.append(list(_.vertices));

print(polygons);




# Triangular polygons
triangles=[];
for _ in polygons:
    if(len(_)==3):triangles.append(_);

print(len(triangles));