3ds max VERY slow (or freezes) after merging objects

I first noticed this issue in December of last year when I was competing in the architectural category of the Vue 3D Environment Competition…<horn toot>which I won by way</horn toot>…no thanks to this bug. I had just upgraded my copy of Forest Pack Pro and was using huge numbers of polygons for plants and bushes, so I thought this was causing the performance hit when trying to merge plant objects for distribution in the scene. Not merely slow performance mind you, but merging, loading, and saving files was taking HOURS or not working at all! When I noticed the exact same thing happening with other more basic scenes, I knew something else was wrong.

I was first led down the trail of thinking it was too many empty note tracks in the file caused by the merging of so many objects. I tried using scripts like THIS and THIS to no avail, but they may work for your if your scenes suffer from note track bloat.

After running into the issue again today on a VERY simple scene, I couldn’t take it anymore and tried one last dive into Google in a desperate search (since merging objects is a critical part of my workflow, and exporting things via FBX was an unacceptable hack). And Voila! I came across a solution that worked for my issue. Turns out it was related to bugs in Track View, but with Retimers instead of note tracks. Don’t ask me how this problem infected my system (I’ve only messed with retimers once to try tweaking some camera path animations…which was an awful experience with terrible results…not at all like retiming in post), but I’m not gonna argue with the fact that running the script below in the Listener Window seems to have been the key to normal 3ds max operation:

COPY THISt=trackviewnodes;n=t[#Retimer_Manager];deleteTrackViewController t n.controller;gc()