At Tocci, we use OST for our 2D quantity surveys and had planned on using Innovaya for 3D quantity surveys. The idea was that we would coordinate these independent quantity surveys and then compile them in Timberline.
Unfortunately, that workflow doesn't seem to be working for us (for a number of reasons).
Luckily, we are now playing with QTO which seems like it could eventually offer a solution. The concept is that QTO combines 2D & 3D quantity surveying in one tool. This information would not have a direct link to Timberline, but we can export to Excel. Better than nothing..