Mesh(ID)

Mesh Data

The mesh data is accessed in object mode and intended for compact storage, for more flexible mesh editing from Python see bmesh.

Blender stores 4 main arrays to define mesh geometry.

Each polygon references a slice in the loop array, this way, polygons do not store vertices or corner data such as UVs directly, only a reference to loops that the polygon uses.

Mesh.loops, Mesh.uv_layers Mesh.vertex_colors are all aligned so the same polygon loop indices can be used to find the UVs and vertex colors as with as the vertices.

To compare mesh API options see: NGons and Tessellation Faces

This example script prints the vertices and UVs for each polygon, assumes the active object is a mesh with UVs.

import bpy

me = bpy.context.object.data
uv_layer = me.uv_layers.active.data

for poly in me.polygons:
    print("Polygon index: {:d}, length: {:d}".format(poly.index, poly.loop_total))

    # Range is used here to show how the polygons reference loops,
    # for convenience 'poly.loop_indices' can be used instead.
    for loop_index in range(poly.loop_start, poly.loop_start + poly.loop_total):
        print("    Vertex: {:d}".format(me.loops[loop_index].vertex_index))
        print("    UV: {!r}".format(uv_layer[loop_index].uv))

base classes — bpy_struct, ID

class bpy.types.Mesh(ID)

Mesh data-block defining geometric surfaces

animation_data

Animation data for this data-block

Type:

AnimData, (readonly)

attributes

Geometry attributes

Type:

AttributeGroupMesh bpy_prop_collection of Attribute, (readonly)

auto_texspace

Adjust active object’s texture space automatically when transforming object

Type:

boolean, default True

color_attributes

Geometry color attributes

Type:

AttributeGroupMesh bpy_prop_collection of Attribute, (readonly)

corner_normals

The “slit” normal direction of each face corner, influenced by vertex normals, sharp faces, sharp edges, and custom normals. May be empty.

Type:

bpy_prop_collection of MeshNormalValue, (readonly)

edges

Edges of the mesh

Type:

MeshEdges bpy_prop_collection of MeshEdge, (readonly)

has_custom_normals

True if there is custom normal data for this mesh

Type:

boolean, default False, (readonly)

is_editmode

True when used in editmode

Type:

boolean, default False, (readonly)

loop_triangle_polygons

The face index for each loop triangle

Type:

bpy_prop_collection of ReadOnlyInteger, (readonly)

loop_triangles

Tessellation of mesh polygons into triangles

Type:

MeshLoopTriangles bpy_prop_collection of MeshLoopTriangle, (readonly)

loops

Loops of the mesh (face corners)

Type:

MeshLoops bpy_prop_collection of MeshLoop, (readonly)

materials
Type:

IDMaterials bpy_prop_collection of Material, (readonly)

normals_domain

The attribute domain that gives enough information to represent the mesh’s normals

Type:

enum in ['POINT', 'FACE', 'CORNER'], default "'FACE'", (readonly)

polygon_normals

The normal direction of each face, defined by the winding order and position of its vertices

Type:

bpy_prop_collection of MeshNormalValue, (readonly)

polygons

Polygons of the mesh

Type:

MeshPolygons bpy_prop_collection of MeshPolygon, (readonly)

radial_symmetry

Number of mirrored regions around a central axis

Type:

int array of 3 items in [1, 64], default (1, 1, 1)

remesh_mode

  • VOXEL Voxel – Use the voxel remesher.

  • QUAD Quad – Use the quad remesher.

Type:

enum in ['VOXEL', 'QUAD'], default "'VOXEL'"

remesh_voxel_adaptivity

Reduces the final face count by simplifying geometry where detail is not needed, generating triangles. A value greater than 0 disables Fix Poles.

Type:

float in [0, 1], default 0.0

remesh_voxel_size

Size of the voxel in object space used for volume evaluation. Lower values preserve finer details.

Type:

float in [0, inf], default 0.1

shape_keys
Type:

Key, (readonly)

skin_vertices

All skin vertices

Type:

bpy_prop_collection of MeshSkinVertexLayer, (readonly)

texco_mesh

Derive texture coordinates from another mesh

Type:

Mesh

texspace_location

Texture space location

Type:

mathutils.Vector of 3 items in [-inf, inf], default (0.0, 0.0, 0.0)

texspace_size

Texture space size

Type:

mathutils.Vector of 3 items in [-inf, inf], default (1.0, 1.0, 1.0)

texture_mesh

Use another mesh for texture indices (vertex indices must be aligned)

Type:

Mesh

total_edge_sel

Selected edge count in editmode

Type:

int in [0, inf], default 0, (readonly)

total_face_sel

Selected face count in editmode

Type:

int in [0, inf], default 0, (readonly)

total_vert_sel

Selected vertex count in editmode

Type:

int in [0, inf], default 0, (readonly)

use_auto_texspace

Adjust active object’s texture space automatically when transforming object

Type:

boolean, default True

use_mirror_topology

Use topology based mirroring (for when both sides of mesh have matching, unique topology)

Type:

boolean, default False

use_mirror_vertex_groups

Mirror the left/right vertex groups when painting. The symmetry axis is determined by the symmetry settings.

Type:

boolean, default True

use_mirror_x

Enable symmetry in the X axis

Type:

boolean, default False

use_mirror_y

Enable symmetry in the Y axis

Type:

boolean, default False

use_mirror_z

Enable symmetry in the Z axis

Type:

boolean, default False

use_paint_bone_selection

Bone selection during painting

Type:

boolean, default True

use_paint_mask

Face selection masking for painting

Type:

boolean, default False

use_paint_mask_vertex

Vertex selection masking for painting

Type:

boolean, default False

use_remesh_fix_poles

Produces fewer poles and a better topology flow

Type:

boolean, default False

use_remesh_preserve_attributes

Transfer all attributes to the new mesh

Type:

boolean, default False

use_remesh_preserve_volume

Projects the mesh to preserve the volume and details of the original mesh

Type:

boolean, default False

uv_layer_clone

UV loop layer to be used as cloning source

Type:

MeshUVLoopLayer

uv_layer_clone_index

Clone UV loop layer index

Type:

int in [0, inf], default 0

uv_layer_stencil

UV loop layer to mask the painted area

Type:

MeshUVLoopLayer

uv_layer_stencil_index

Mask UV loop layer index

Type:

int in [0, inf], default 0

uv_layers

All UV loop layers

Type:

UVLoopLayers bpy_prop_collection of MeshUVLoopLayer, (readonly)

vertex_colors

Legacy vertex color layers. Deprecated, use color attributes instead.

Type:

LoopColors bpy_prop_collection of MeshLoopColorLayer, (readonly)

vertex_normals

The normal direction of each vertex, defined as the average of the surrounding face normals

Type:

bpy_prop_collection of MeshNormalValue, (readonly)

vertices

Vertices of the mesh

Type:

MeshVertices bpy_prop_collection of MeshVertex, (readonly)

edge_creases

Edge crease values for subdivision surface, corresponding to the “crease_edge” attribute.

(readonly)

edge_keys

(readonly)

vertex_creases

Vertex crease values for subdivision surface, corresponding to the “crease_vert” attribute.

(readonly)

vertex_paint_mask

Mask values for sculpting and painting, corresponding to the “.sculpt_mask” attribute.

(readonly)

transform(matrix, *, shape_keys=False)

Transform mesh vertices by a matrix (Warning: inverts normals if matrix is negative)

Parameters:

  • matrix (mathutils.Matrix of 4 * 4 items in [-inf, inf]) – Matrix

  • shape_keys (boolean, (optional)) – Transform Shape Keys

flip_normals()

Invert winding of all polygons (clears tessellation, does not handle custom normals)

set_sharp_from_angle(*, angle=3.14159)

Reset and fill the “sharp_edge” attribute based on the angle of faces neighboring manifold edges

Parameters:

angle (float in [0, 3.14159], (optional)) – Angle, Angle between faces beyond which edges are marked sharp

split_faces()

Split faces based on the edge angle

calc_tangents(*, uvmap='')

Compute tangents and bitangent signs, to be used together with the custom normals to get a complete tangent space for normal mapping (custom normals are also computed if not yet present)

Parameters:

uvmap (string, (optional, never None)) – Name of the UV map to use for tangent space computation

free_tangents()

Free tangents

calc_loop_triangles()

Calculate loop triangle tessellation (supports editmode too)

calc_smooth_groups(*, use_bitflags=False, use_boundary_vertices_for_bitflags=False)

Calculate smooth groups from sharp edges

Parameters:

  • use_bitflags (boolean, (optional)) – Produce bitflags groups instead of simple numeric values

  • use_boundary_vertices_for_bitflags (boolean, (optional)) – Also consider different smoothgroups sharing only vertices (but without any common edge) as neighbors, preventing them from sharing the same bitflag value. Only effective when use_bitflags is set. WARNING: Will overflow (run out of available bits) easily with some types of topology, e.g. large fans of sharp edges

Returns:

poly_groups, Smooth Groups, int array of 1 items in [-inf, inf]

groups, Total number of groups, int in [0, inf]

Return type:

(int array of 1 items in [-inf, inf], int in [0, inf])

normals_split_custom_set(normals)

Define custom normals of this mesh (use zero-vectors to keep auto ones)

Parameters:

normals (float multi-dimensional array of 1 * 3 items in [-1, 1]) – Normals

normals_split_custom_set_from_vertices(normals)

Define custom normals of this mesh, from vertices’ normals (use zero-vectors to keep auto ones)

Parameters:

normals (float multi-dimensional array of 1 * 3 items in [-1, 1]) – Normals

update(*, calc_edges=False, calc_edges_loose=False)

update

Parameters:

  • calc_edges (boolean, (optional)) – Calculate Edges, Force recalculation of edges

  • calc_edges_loose (boolean, (optional)) – Calculate Loose Edges, Calculate the loose state of each edge

update_gpu_tag()

update_gpu_tag

unit_test_compare(*, mesh=None, threshold=7.1526e-06)

unit_test_compare

Parameters:

  • mesh (Mesh, (optional)) – Mesh to compare to

  • threshold (float in [0, inf], (optional)) – Threshold, Comparison tolerance threshold

Returns:

Return value, String description of result of comparison

Return type:

string, (never None)

clear_geometry()

Remove all geometry from the mesh. Note that this does not free shape keys or materials.

validate(*, verbose=False, clean_customdata=True)

Validate geometry, return True when the mesh has had invalid geometry corrected/removed

Parameters:

  • verbose (boolean, (optional)) – Verbose, Output information about the errors found

  • clean_customdata (boolean, (optional)) – Clean Custom Data, Remove temp/cached custom-data layers, like e.g. normals…

Returns:

Result

Return type:

boolean

validate_material_indices()

Validate material indices of polygons, return True when the mesh has had invalid indices corrected (to default 0)

Returns:

Result

Return type:

boolean

count_selected_items()

Return the number of selected items (vert, edge, face)

Returns:

Result

Return type:

int array of 3 items in [0, inf]

edge_creases_ensure()
edge_creases_remove()
from_pydata(vertices, edges, faces, shade_flat=True)

Make a mesh from a list of vertices/edges/faces Until we have a nicer way to make geometry, use this.

Parameters:

  • vertices (Iterable[Sequence[float]]) – float triplets each representing (X, Y, Z) eg: [(0.0, 1.0, 0.5), …].

  • edges (Iterable[Sequence[int]]) –

    int pairs, each pair contains two indices to the vertices argument. eg: [(1, 2), …]

    When an empty iterable is passed in, the edges are inferred from the polygons.

  • faces (Iterable[Sequence[int]]) – iterator of faces, each faces contains three or more indices to the vertices argument. eg: [(5, 6, 8, 9), (1, 2, 3), …]

Warning

Invalid mesh data (out of range indices, edges with matching indices, 2 sided faces… etc) are not prevented. If the data used for mesh creation isn’t known to be valid, run Mesh.validate after this function.

shade_flat()

Render and display faces uniform, using face normals, setting the “sharp_face” attribute true for every face

shade_smooth()

Render and display faces smooth, using interpolated vertex normals, removing the “sharp_face” attribute

vertex_creases_ensure()
vertex_creases_remove()
vertex_paint_mask_ensure()
vertex_paint_mask_remove()
classmethod bl_rna_get_subclass(id, default=None, /)
Parameters:

id (str) – The RNA type identifier.

Returns:

The RNA type or default when not found.

Return type:

bpy.types.Struct subclass

classmethod bl_rna_get_subclass_py(id, default=None, /)
Parameters:

id (str) – The RNA type identifier.

Returns:

The class or default when not found.

Return type:

type

Inherited Properties

Inherited Functions

References