Export : uneditable 3d object

Hey,
i made object with 40,000 faces.
My primal goal is to duplicate this object and build a house with it (its a building block).

When i was doing that, my computer ( and blender ) started to work really slow. So i cant continue to
work on this project like that.
I build/duplicated around 80 objects…with total of 5,000,000 faces. That explains slowed down performance.

Now i want to export this object as single 3d object ( less faces, edges ) as possible.
Kind of an uneditable object whose only function would be to move around and duplicate.
So i would later start new blender project and import this new object and start building house from stretch again.
With hope it doesnt slow down performance again.

So my question is:
What export model would u recommend ? 3ds, obj…?
or
Can you find any other solution to reduce amount of faces my object have ?

Please help,
and
Thank you very much !!

What export model would u recommend ? 3ds, obj…?
In what application are you going to use this object ?. If you are goint to use that object in blender then you just save it as a normal blend file. Use can use Shift+F1 to append or link that object into you current blend file. If you also use linked duplicates (Alt+D) instead of normal duplicates (Shift+D) or Dupligroups to make instances of the original object so uses less memory than separate objects

Can you find any other solution to reduce amount of faces my object have ?

You can reduced polycount by manually deleting unwanted edge loops (X) or unnecessary faces. You can use an external application to decimate the mesh to a lower poly count or use blenders decimate modifier The results will vary depending on the source mesh and level of decimation


what sort of brick ?? even a Lego block wouldn’t have that many faces !!
show us the brick and you’ll get loads of ideas to reduce the polycount