Combine on takes forever on large amount of objects

[djpuckett]

I design small buildings (n scale model railroad size). A lot of my designs have bricks for the walls. There can be hundreds of bricks in one design. Trying to use combine to make the brick wall one object takes so long, it is unusable. I have had it run for 2 days and still not complete.
Same with exporting the same model.

How can hundreds of objects be combined with any speed? I can do it in Tinkercad altough it does take some time but not as much as what is happening with Mattercontrol. I really want to use Mattercontrol but the combine function is just taking too long. I don't know of any other way to design a complete object without using combine.