Yes the physics is for the dropped bricks and boards. If I save my scene after rework and before doing the calculations, close carrara, restart, reload, then run the physics it's no issue and does it fast; about ten minutes. Which is quick for the number of objects dropped. Not sure if the issue is a memory leak, or the DAZ tmp folder filling up. But it's an easy fix/workaround.

I don't have HD lighting turned on in that render, it was just a quicky to see how it looked. Today I am doing textures, got the uvmap for the bridge and am working on a brick texture that matches the background better, and making a alpha map for the metal bridge parts I don't want visible.

Off topic. Had the bejeezus scared out of me this morning. Turned on my comp and W8.1 wouldn't take my pass.   After an hour of fumming and assuming my comp had been highjacked, I was locked out, and I thought I was going to have to buy a hard copy of windows 8. I checked my pass visualy; clicked the eye to see the letters of my pass... shift key wasn't working, had some grit caught under it