If I understand, you are using the Unity tool because UE4 is breaking up your original building FBX?
You can select all of the individual parts in the UE4 Content Browser at once. Then drag them into the viewport together. All of the elements will keep their relative positions with respect to eachother.
On the subject of texturing; Blender is embarrasingly bad at exporting FBX materials. There are two options.
1/ Bake the textures onto the geometry. (Render-Tab/Bake with Full Render)
2/ Delete all of the existing materials then assign one single material. Then do a fresh UV/Lightmap unwrap. You will need to create a new texture file if you do this.
Note: Blender allows you to merge meshes also. Select All, then go to Object/Join.
Thank you for a reply.
I tried a method to bake texture of blender, but gave it up to take too much time.
I almost got along well afterwards without taking it to blender and unity when I imported directly in UE4.
(some material is displayed saying “a compilation error occurred to level SM5 warning, material”.
Glad when you can show me it if there is a workaround.)
It is a talk very shameful.
I should have taken it to UE4 from a beginning.
When I chose all the individual parts and dragged them in a viewport, I got along well.
Thank you very much.
(when FBX import was optional and checked it in “Combine Meshes” if I checked it in various ways later, I knew that mesh was coupled.)
By the answer that you gave, this question wants to be closed.
Thank you.
I have never encountered the SM5 error myself. You may find a solution in this post.
Note: No shame. Many normal people secretly experiment with Unity Technologies. However, attempting to use it together with Unreal will always complicate debugging.