I would suggest to try deactivate the Display - Viewport - Use DirectX
acceleration option, to check if there is any improvement.
Anyway, would you mind to send us your scene to firstname.lastname@example.org to analyse it here? In case of big file size, please use a web sharing service as WeTransfer
. Also please specify which 3ds Max / Forest Pack & RailClone / renderer releases are you using. Thanks in advance.
In case, the 3ds Max crashes, would you please save and send us the minidump file of the crash? (You can get the minidump clicking "View report details->View report contents", checking the path of the "3dsmax_minidump.dmp
" file and making a copy of it, before closing the 3ds Max Error Report window).