顺序导入.obj文件变得非常快速

Question

我编写了一个非常简单的脚本，逐个导入许多obj文件并呈现它们。导入的网格有~10k到~120k的顶点。渲染后，我会在导入下一个网格之前完全删除导入的网格（及其数据块）。但是，随着for循环的进行，导入过程变得非常慢。我注意到导入函数开始以奇怪的方式运行，导入对象需要花费大量时间。我不确定为什么会这样。最初我认为内存问题导致了这一点，但我认为删除数据块应解决内存泄漏问题。即使不对导入的对象进行任何渲染或任何操作，也会发生这种情况。以下是导入网格时导入功能打印的实例：

(  0.0002 sec |   0.0002 sec) Importing OBJ '/data/e1f2651d55aecd7d8f2b6fca0ec9a39dn7a9/models/model.obj'...
(  0.0308 sec |   0.0306 sec) Parsing OBJ file...
(  1.8534 sec |   1.8511 sec) Done, loading materials and images...
(  2.0450 sec |   2.0426 sec) Done, building geometries (verts:72707 faces:137005 materials: 44 smoothgroups:0) ...
(  5.4944 sec |   5.4921 sec) Done.
(  5.4946 sec |   5.4945 sec) Finished importing: 'data/e1f2651d55aecd7d8f2b6fca0ec9a39dn7a9/models/model.obj'
Progress: 100.00%

随着导入更多对象，导入函数的行为越来越慢，即使对于更简单的形状（例如~12k顶点），您将得到如下内容：

(  0.0002 sec |   0.0002 sec) Importing OBJ '/data/jjgd2e3f46f7cc1e8ba69a5e14689f7b974/models/model.obj'...
  (  0.0266 sec |   0.0263 sec) Parsing OBJ file...
    (  0.7060 sec |   0.6793 sec) Done, loading materials and images...
    (  3.0993 sec |   3.0726 sec) Done, building geometries (verts:12668 faces:43914 materials: 28 smoothgroups:0) ...
    ( 18.6672 sec |  18.6405 sec) Done.
  ( 18.6673 sec |  18.6671 sec) Finished importing: '/data/jjgd2e3f46f7cc1e8ba69a5e14689f7b974/models/model.obj'
Progress: 100.00%

但是，如果首先导入具有~12k顶点的相同对象，我得到如下内容：

(  0.0001 sec |   0.0001 sec) Importing OBJ '/data/jjgd2e3f46f7cc1e8ba69a5e14689f7b974/models/model.obj'...
  (  0.0025 sec |   0.0023 sec) Parsing OBJ file...
    (  0.5541 sec |   0.5516 sec) Done, loading materials and images...
    (  0.5572 sec |   0.5547 sec) Done, building geometries (verts:12668 faces:43914 materials: 28 smoothgroups:0) ...
    (  1.0660 sec |   1.0635 sec) Done.
  (  1.0663 sec |   1.0662 sec) Finished importing: '/data/jjgd2e3f46f7cc1e8ba69a5e14689f7b974/models/model.obj'
Progress: 100.00%

这是我的代码：

#blenderClass.py
import bpy, math, timeit
import numpy as np

class Blender(object):
    def __init__(self):
        self.bpy = bpy
        self.scene = self.bpy.context.scene
        self.scene.render.use_sequencer = False

        # Some memory management
        self.scene.render.use_free_image_textures = True
        self.bpy.context.user_preferences.edit.undo_steps = 0
        self.bpy.context.user_preferences.edit.undo_memory_limit = 60
        self.bpy.context.user_preferences.edit.use_global_undo = False

    def setupScene(self):
        self.removeCamera()
        self.removeMesh()
        self.bpy.ops.object.camera_add(location=tuple(1, -0.5, 0.3))
        self.pointObjTo(self.scene.objects.active, (0.0, 0.0, 0.0)) # My objects are all centered on (0, 0, 0)

    def render(self, objPath):
        self.bpy.ops.import_scene.obj(filepath=objPath)
        self.removeMesh()
        self.removeDataBlocks()


    def removeDataBlocks(self, removeAll=False):
        # Removes unlinked data blocks and prevents memory leakage

        for block in self.bpy.data.meshes:
            if block.users == 0:
                self.bpy.data.meshes.remove(block)

        for block in self.bpy.data.materials:
            if block.users == 0:
                self.bpy.data.materials.remove(block)

        for block in self.bpy.data.textures:
            if block.users == 0:
                self.bpy.data.textures.remove(block)

        for block in self.bpy.data.images:
            if block.users == 0:
                self.bpy.data.images.remove(block)


    def removeMesh(self, layer = -1):
        for obj in self.scene.objects:
            if obj.type == 'MESH':
                obj.select = True
            else:
                obj.select = False
        self.bpy.ops.object.delete()


    def removeCamera(self):
        for obj in self.scene.objects:
            if obj.type == 'CAMERA':
                obj.select = True
            else:
                obj.select = False
        self.bpy.ops.object.delete()


    def pointObjTo(self, obj, xyzTarget):
        # This function operates directly on the input object (obj)
        from mathutils import Vector
        xyzTarget = Vector(xyzTarget)
        direction = xyzTarget - obj.location
        rot_quat = direction.to_track_quat('-Z', 'Y')
        obj.rotation_euler = rot_quat.to_euler()

这就是我运行代码的方式：

#main.py
import blenderClass import Blender
blender = Blender()
blender.setupScene()

objPaths = ['obj1.obj', 'obj2.obj', 'obj3.obj', 'obj4.obj']

for objPath in objPaths:
    blender.render(objPath)

不幸的是我无法以精确的方式监视系统资源（我在服务器上运行它）但我担心导入功能不会释放一些资源或者某种程度上内存被填满。我尝试在桌面计算机中将许多形状导入Blender，并在手动删除网格后执行数据块删除功能。我的猜测是，当我导入许多3D形状时，即使它是400MB，也可以将内存消耗降低到10MB左右。如果你想尝试上面的代码，也许一个简单的解决方案是使用原始形状，如球体，立方体等，并细分它们，使它们有很多顶点（可能~50-70k）并将它们存储为obj。我认为有大约10-15个obj文件应该可以工作。在为我导入第3个或第4个对象后，事情开始变得很慢。

我不确定这是否相关，但我称之为Blender函数的方式不是通过在background中调用它。相反，我手动编译Blender 2.79作为Python模块，并通过我机器上安装的Python中的import bpy导入其API。

虽然我相当确定删除数据块会释放内存，但我也尝试使用Python的垃圾收集器，但它没有帮助。

有谁知道我做错了什么？我很迷茫 ...