diff --git a/inc/hgl/graph/MaterialRenderList.h b/inc/hgl/graph/MaterialRenderList.h
index 5f6980c6..1534291a 100644
--- a/inc/hgl/graph/MaterialRenderList.h
+++ b/inc/hgl/graph/MaterialRenderList.h
@@ -3,7 +3,8 @@
 #include<hgl/graph/VKVBOList.h>
 
 VK_NAMESPACE_BEGIN
-class RenderAssignBuffer;
+class RenderL2WBuffer;
+class RenderMIBuffer;
 
 /**
 * 同一材质的对象渲染列表
@@ -19,7 +20,8 @@ class MaterialRenderList
 
 private:
 
-    RenderAssignBuffer *assign_buffer;
+    RenderL2WBuffer *l2w_buffer;
+    RenderMIBuffer *mi_buffer;
 
     struct RenderItem
     {
@@ -39,8 +41,6 @@ private:
     DataArray<RenderItem> ri_array;
     uint ri_count;
 
-    bool has_l2w;
-    bool has_mi;
     VkDeviceSize l2w_buffer_size[4];
 
     void StatMI();
diff --git a/src/SceneGraph/MaterialRenderList.cpp b/src/SceneGraph/MaterialRenderList.cpp
index 1a8908fe..9d347a9d 100644
--- a/src/SceneGraph/MaterialRenderList.cpp
+++ b/src/SceneGraph/MaterialRenderList.cpp
@@ -53,13 +53,15 @@ MaterialRenderList::MaterialRenderList(GPUDevice *d,bool l2w,Material *m)
     cmd_buf=nullptr;
     material=m;
 
-    has_l2w=l2w;
-    has_mi=material->HasMI();
-
-    if(has_l2w||has_mi)
-        assign_buffer=new RenderAssignBuffer(d,has_l2w,material->GetMIDataBytes());
+    if(l2w)
+        l2w_buffer=new RenderL2WBuffer(device);
     else
-        assign_buffer=nullptr;
+        l2w_buffer=nullptr;
+
+    if(material->HasMI())
+        mi_buffer=new RenderMIBuffer(device,material->GetMIDataBytes());
+    else
+        mi_buffer=nullptr;
 
     vbo_list=new VBOList(material->GetVertexInput()->GetCount());
 }
@@ -67,7 +69,8 @@ MaterialRenderList::MaterialRenderList(GPUDevice *d,bool l2w,Material *m)
 MaterialRenderList::~MaterialRenderList()
 {
     SAFE_CLEAR(vbo_list);
-    SAFE_CLEAR(assign_buffer)
+    SAFE_CLEAR(mi_buffer);
+    SAFE_CLEAR(l2w_buffer);
 }
 
 void MaterialRenderList::Add(Renderable *ri,const Matrix4f &mat)
@@ -91,13 +94,15 @@ void MaterialRenderList::End()
 
     Stat();
 
-    if(assign_buffer)
+    if(l2w_buffer)
     {
-        if(has_mi)
-            StatMI();
+        l2w_buffer->WriteNode(rn_list.GetData(),node_count);
+    }
 
-        //写入LocalToWorld数据
-        assign_buffer->WriteNode(rn_list.GetData(),node_count,mi_set);
+    if(mi_buffer)
+    {
+        StatMI();
+        mi_buffer->WriteNode(rn_list.GetData(),node_count,mi_set);
     }
 }
 
@@ -182,16 +187,16 @@ bool MaterialRenderList::Bind(const VertexInputData *vid,const uint ri_index)
         vbo_list->Add(vid->buffer_list,vid->buffer_offset,vid->binding_count);
     }
 
-    if(has_l2w)//LocalToWorld组，由RenderList合成
+    if(l2w_buffer)//LocalToWorld组，由RenderList合成
     {
         for(uint i=0;i<4;i++)
             l2w_buffer_size[i]=ri_index*16;                        //mat4每列都是rgba32f，自然是16字节
 
-        vbo_list->Add(assign_buffer->GetLocalToWorldVBO(),l2w_buffer_size,4);
+        vbo_list->Add(l2w_buffer->GetVBO(),l2w_buffer_size,4);
     }
 
-    if(has_mi) //材质实例组
-        vbo_list->Add(assign_buffer->GetMIVBO(),MI_VBO_STRIDE_BYTES*ri_index);
+    if(mi_buffer) //材质实例组
+        vbo_list->Add(mi_buffer->GetVBO(),MI_VBO_STRIDE_BYTES*ri_index);
 
     //if(!vbo_list.IsFull()) //Joint组，暂未支持
     //{
@@ -281,8 +286,8 @@ void MaterialRenderList::Render(RenderCmdBuffer *rcb)
     last_pipeline   =nullptr;
     last_vid        =nullptr;
 
-    if(assign_buffer)
-        assign_buffer->Bind(material);
+    if(mi_buffer)
+        mi_buffer->Bind(material);
 
     cmd_buf->BindDescriptorSets(material);
 
diff --git a/src/SceneGraph/RenderAssignBuffer.cpp b/src/SceneGraph/RenderAssignBuffer.cpp
index 16b039a7..332d1b01 100644
--- a/src/SceneGraph/RenderAssignBuffer.cpp
+++ b/src/SceneGraph/RenderAssignBuffer.cpp
@@ -8,37 +8,21 @@
 #include<hgl/graph/mtl/UBOCommon.h>
 
 VK_NAMESPACE_BEGIN
-RenderAssignBuffer::RenderAssignBuffer(GPUDevice *dev,const bool has_l2w,const uint mi_bytes)
+RenderL2WBuffer::RenderL2WBuffer(GPUDevice *dev)
 {
     hgl_zero(*this);
 
     device=dev;
-
-    mi_data_bytes=mi_bytes;
 }
 
-void RenderAssignBuffer::Bind(Material *mtl)const
+void RenderL2WBuffer::Clear()
 {
-    if(!mtl)return;
-
-    if(!mtl->HasMI())
-        return;
-
-    mtl->BindUBO(DescriptorSetType::PerMaterial,mtl::SBS_MaterialInstance.name,ubo_mi);
-}
-
-void RenderAssignBuffer::Clear()
-{
-    SAFE_CLEAR(ubo_mi);
-    SAFE_CLEAR(vbo_mi);
-
     SAFE_CLEAR(l2w_vbo[0])
     SAFE_CLEAR(l2w_vbo[1])
     SAFE_CLEAR(l2w_vbo[2])
     SAFE_CLEAR(l2w_vbo[3])
 
     node_count=0;
-    mi_count=0;
 }
 
 #ifdef _DEBUG
@@ -62,7 +46,7 @@ namespace
 }
 #endif//_DEBUG
 
-void RenderAssignBuffer::Alloc(const uint nc,const uint mc)
+void RenderL2WBuffer::Alloc(const uint nc)
 {
     Clear();
 
@@ -76,6 +60,78 @@ void RenderAssignBuffer::Alloc(const uint nc,const uint mc)
         }
     }
 
+#ifdef _DEBUG
+    DebugUtils *du=device->GetDebugUtils();
+
+    if(du)
+    {
+        for(int i=0;i<4;i++)
+        {
+            du->SetBuffer(l2w_buffer[i],l2w_buffer_name[i]);
+            du->SetDeviceMemory(l2w_vbo[i]->GetVkMemory(),l2w_memory_name[i]);
+        }
+    }
+#endif//_DEBUG
+}
+
+void RenderL2WBuffer::WriteNode(RenderNode *render_node,const uint count)
+{
+    RenderNode *rn;
+
+    Alloc(count);
+
+    glm::vec4 *tp;
+
+    for(uint col=0;col<4;col++)
+    {
+        tp=(glm::vec4 *)(l2w_vbo[col]->Map());
+
+        rn=render_node;
+
+        for(uint i=0;i<count;i++)
+        {
+            *tp=rn->local_to_world[col];
+            ++tp;
+            ++rn;
+        }
+
+        l2w_vbo[col]->Unmap();
+    }
+}
+VK_NAMESPACE_END
+
+VK_NAMESPACE_BEGIN
+RenderMIBuffer::RenderMIBuffer(GPUDevice *dev,const uint mi_bytes)
+{
+    hgl_zero(*this);
+
+    device=dev;
+
+    mi_data_bytes=mi_bytes;
+}
+
+void RenderMIBuffer::Bind(Material *mtl)const
+{
+    if(!mtl)return;
+
+    mtl->BindUBO(DescriptorSetType::PerMaterial,mtl::SBS_MaterialInstance.name,ubo_mi);
+}
+
+void RenderMIBuffer::Clear()
+{
+    SAFE_CLEAR(ubo_mi);
+    SAFE_CLEAR(vbo_mi);
+
+    mi_count=0;
+    node_count=0;
+}
+
+void RenderMIBuffer::Alloc(const uint nc,const uint mc)
+{
+    Clear();
+
+    node_count=nc;
+
     if(mi_data_bytes>0&&mc>0)
     {
         mi_count=mc;
@@ -91,84 +147,45 @@ void RenderAssignBuffer::Alloc(const uint nc,const uint mc)
         
         if(du)
         {
-            if(l2w_buffer[0])
-            {
-                for(int i=0;i<4;i++)
-                {
-                    du->SetBuffer(l2w_buffer[i],l2w_buffer_name[i]);
-                    du->SetDeviceMemory(l2w_vbo[i]->GetVkMemory(),l2w_memory_name[i]);
-                }
-            }
+            du->SetBuffer(ubo_mi->GetBuffer(),"UBO:Buffer:MaterialInstance");
+            du->SetDeviceMemory(ubo_mi->GetVkMemory(),"UBO:Memory:MaterialInstance");
 
-            if(ubo_mi)
-            {
-                du->SetBuffer(ubo_mi->GetBuffer(),"UBO:Buffer:MaterialInstance");
-                du->SetDeviceMemory(ubo_mi->GetVkMemory(),"UBO:Memory:MaterialInstance");
-            }
-
-            if(vbo_mi)
-            {
-                du->SetBuffer(vbo_mi->GetBuffer(),"VBO:Buffer:MaterialInstanceID");
-                du->SetDeviceMemory(vbo_mi->GetVkMemory(),"VBO:Memory:MaterialInstanceID");
-            }
+            du->SetBuffer(vbo_mi->GetBuffer(),"VBO:Buffer:MaterialInstanceID");
+            du->SetDeviceMemory(vbo_mi->GetVkMemory(),"VBO:Memory:MaterialInstanceID");
         }
     #endif//_DEBUG
 }
 
-void RenderAssignBuffer::WriteNode(RenderNode *render_node,const uint count,const MaterialInstanceSets &mi_set)
+void RenderMIBuffer::WriteNode(RenderNode *render_node,const uint count,const MaterialInstanceSets &mi_set)
 {
     RenderNode *rn;
 
     Alloc(count,mi_set.GetCount());
 
-    if(l2w_buffer[0])
+    uint8 *mip=(uint8 *)(ubo_mi->Map());
+
+    for(MaterialInstance *mi:mi_set)
     {
-        glm::vec4 *tp;
+        memcpy(mip,mi->GetMIData(),mi_data_bytes);
+        mip+=mi_data_bytes;
+    }
 
-        for(uint col=0;col<4;col++)
+    ubo_mi->Unmap();
+
+    uint16 *idp=(uint16 *)(vbo_mi->Map());
+
+    {
+        rn=render_node;
+
+        for(uint i=0;i<count;i++)
         {
-            tp=(glm::vec4 *)(l2w_vbo[col]->Map());
+            *idp=mi_set.Find(rn->ri->GetMaterialInstance());
+            ++idp;
 
-            rn=render_node;
-
-            for(uint i=0;i<count;i++)
-            {
-                *tp=rn->local_to_world[col];
-                ++tp;
-                ++rn;
-            }
-
-            l2w_vbo[col]->Unmap();
+            ++rn;
         }
     }
 
-    if(ubo_mi)
-    {
-        uint8 *mip=(uint8 *)(ubo_mi->Map());
-
-        for(MaterialInstance *mi:mi_set)
-        {
-            memcpy(mip,mi->GetMIData(),mi_data_bytes);
-            mip+=mi_data_bytes;
-        }
-
-        ubo_mi->Unmap();
-
-        uint16 *idp=(uint16 *)(vbo_mi->Map());
-
-        {
-            rn=render_node;
-
-            for(uint i=0;i<count;i++)
-            {
-                *idp=mi_set.Find(rn->ri->GetMaterialInstance());
-                ++idp;
-
-                ++rn;
-            }
-        }
-
-        vbo_mi->Unmap();
-    }
+    vbo_mi->Unmap();
 }
 VK_NAMESPACE_END
diff --git a/src/SceneGraph/RenderAssignBuffer.h b/src/SceneGraph/RenderAssignBuffer.h
index 4a10593a..a4a45695 100644
--- a/src/SceneGraph/RenderAssignBuffer.h
+++ b/src/SceneGraph/RenderAssignBuffer.h
@@ -25,13 +25,8 @@ VK_NAMESPACE_BEGIN
 struct RenderNode;
 class MaterialInstance;
 
-/*
-* 渲染节点额外提供的数据
-*/
-class RenderAssignBuffer
+class RenderL2WBuffer
 {
-private:
-
     GPUDevice *device;
 
     uint node_count;                    ///<渲染节点数量
@@ -39,6 +34,35 @@ private:
     VBO *l2w_vbo[4];
     VkBuffer l2w_buffer[4];
 
+private:
+
+    void Alloc(const uint nc);
+
+    void Clear();
+
+public:
+
+    const VkBuffer *GetVBO()const{return l2w_buffer;}
+
+public:
+
+    RenderL2WBuffer(GPUDevice *dev);
+    ~RenderL2WBuffer(){Clear();}
+
+    void WriteNode(RenderNode *render_node,const uint count);
+};//class RenderL2WBuffer
+
+/*
+* 渲染节点额外提供的数据
+*/
+class RenderMIBuffer
+{
+private:
+
+    GPUDevice *device;
+
+    uint node_count;                    ///<渲染节点数量
+
     uint32_t mi_data_bytes;             ///<材质实例数据字节数
     uint32_t mi_count;                  ///<材质实例数量
     DeviceBuffer *ubo_mi;               ///<材质实例数据
@@ -54,17 +78,20 @@ private:
 
 public:
 
-    const VkBuffer *GetLocalToWorldVBO()const{return l2w_buffer;}
-    const VkBuffer  GetMIVBO          ()const{return mi_buffer;}
+    const VkBuffer GetVBO()const{return mi_buffer;}
 
     void Bind(Material *)const;
 
 public:
 
-    RenderAssignBuffer(GPUDevice *dev,const bool has_l2w,const uint32_t mi_bytes);
-    ~RenderAssignBuffer(){Clear();}
+    RenderMIBuffer(GPUDevice *dev,const uint32_t mi_bytes);
+    ~RenderMIBuffer(){Clear();}
 
-    void WriteNode(RenderNode *render_node,const uint count,const MaterialInstanceSets &mi_set);
+    //下一代，将MaterialInstanceSets使用提前化，这样不用每一次绘制都重新写入MI DATA，可以提升效率。
+    //虽然这样就不自动化了，但我们要的就是不自动化。
+    //必须在外部全部准备好MaterialInstanceSets，然后一次性写入。
+    //渲染时找不到就直接用0号材质实例
 
-};//struct RenderAssignBuffer
+    void WriteNode(RenderNode *render_node,const uint nc,const MaterialInstanceSets &mi_set);
+};//struct RenderMIBuffer
 VK_NAMESPACE_END