blender – join two meshes

https://gamedev.stackexchange.com/questions/33843/how-to-merge-two-objects-in-blender

On each object you will choose one or more faces that will be removed. In between these faces will be your connection.

• Select both objects in object mode. Press Ctrl+J to join the objects into one. Then enter edit mode and change to face manipulation mode.

  

• Remove the faces that will be joined. Select them and press X, remember to delete faces, not vertices.

• Switch back to Vertex manipulation mode. Join the objects by selecting the corresponding vertices from each object and using F to create a new face. For example, in the image below I’ve selected two of the vertices on the sphere and one on the cuboid. When I press F Blender will create a new triangle face there. It also supports quads if the vertices share a common plane. I typically limit the vertex selection to three or four vertices at a time, I tend to think I know where I want the faces to be better than Blender. But you can try selecting all the vertices and see what Blender does for you.

• Continue the previous step until all faces are joined.