BMesh

basic

import bmesh

create empty

# Get a BMesh representation
bm = bmesh.new()   # create an empty BMesh

load from mesh

bm.from_mesh(mesh)

apply to mesh

# Finish up, write the bmesh back to the mesh
bm.to_mesh(mesh)
bm.free()  # free and prevent further access

vertex

add

v = bm.verts.new((x, y, z))

vertex group

layer = bm.verts.layers.deform.active

bm.verts[vertex_index][layer][vertex_group_index] = weight

morph target

layer = bm.verts.layers.shape.new(target.name)

loop

uv_layer

loop の UV layer に格納されている。 vert から接続する loop を得て、その uv layer から値を得る。

uv_layer = bm.loops.layers.uv.new(UV_LAYER_NAME)

layer = bm.loops.layers.uv.active

def uv_from_vert_first(uv_layer, v):
    for l in v.link_loops:
        return l[uv_layer].uv
    return None

walker

https://devtalk.blender.org/t/walking-edge-loops-across-a-mesh-from-c-to-python/14297/4

source

  • source\blender\bmesh\bmesh.h

  • source\blender\bmesh\bmesh_class.h

  • source\blender\bmesh\intern\bmesh_mesh.h

typedef struct BMesh {
  int totvert, totedge, totloop, totface;
  int totvertsel, totedgesel, totfacesel;

  /**
   * Flag index arrays as being dirty so we can check if they are clean and
   * avoid looping over the entire vert/edge/face/loop array in those cases.
   * valid flags are: `(BM_VERT | BM_EDGE | BM_FACE | BM_LOOP)`
   */
  char elem_index_dirty;

  /**
   * Flag array table as being dirty so we know when its safe to use it,
   * or when it needs to be re-created.
   */
  char elem_table_dirty;

  /* element pools */
  struct BLI_mempool *vpool, *epool, *lpool, *fpool;

  /* mempool lookup tables (optional)
   * index tables, to map indices to elements via
   * BM_mesh_elem_table_ensure and associated functions.  don't
   * touch this or read it directly.\
   * Use BM_mesh_elem_table_ensure(), BM_vert/edge/face_at_index() */
  BMVert **vtable;
  BMEdge **etable;
  BMFace **ftable;

  /* size of allocated tables */
  int vtable_tot;
  int etable_tot;
  int ftable_tot;

  /* operator api stuff (must be all NULL or all alloc'd) */
  struct BLI_mempool *vtoolflagpool, *etoolflagpool, *ftoolflagpool;

  uint use_toolflags : 1;

  int toolflag_index;

  CustomData vdata, edata, ldata, pdata;

#ifdef USE_BMESH_HOLES
  struct BLI_mempool *looplistpool;
#endif

  struct MLoopNorSpaceArray *lnor_spacearr;
  char spacearr_dirty;

  /* Should be copy of scene select mode. */
  /* Stored in #BMEditMesh too, this is a bit confusing,
   * make sure they're in sync!
   * Only use when the edit mesh cant be accessed - campbell */
  short selectmode;

  /* ID of the shape key this bmesh came from */
  int shapenr;

  int totflags;
  ListBase selected;

  /**
   * The active face.
   * This is kept even when unselected, mainly so UV editing can keep showing the
   * active faces image while the selection is being modified in the 3D viewport.
   *
   * Without this the active image in the UV editor would flicker in a distracting way
   * while changing selection in the 3D viewport.
   */
  BMFace *act_face;

  /** List of #BMOpError, used for operator error handling. */
  ListBase errorstack;

  /**
   * Keep a single reference to the Python instance of this #BMesh (if any exists).
   *
   * This allows save invalidation of a #BMesh when it's freed,
   * so the Python object will report it as having been removed,
   * instead of crashing on invalid memory access.
   */
  void *py_handle;
} BMesh;