So, PTC helped to find the issue. Seems like the browser kills the cad-optimizer if it runs too long. Only help till now is to run the optimizer via command prompt. To make working with it a bit easier, we wrote a bat file. Here is how it works:
1. Make folder on Desktop
2. Crate file with ending .bat (e.g. create textfile and rename ending from .txt to .bat
3. open file with editor and paste code from down below
4. Place desired pvz-file in folder
5. start CAD-optimizer.bat
6. go through steps note: If you want to place it in annother directory click right on bat and open with editor. Change part "C:\Users\%name%\Desktop\pvz_tool" to the desired directory
@echo off color 4a echo pvz optimizer starter tool set name="" set /p name=please enter your windows-username (needed to find directory): set input="" set /p input=type in the file name without data ending: set outputname="" set /p outputname=type in the desired output file name: set aufloesung="" set /p aufloesung=type in resolution (low/med/high): "C:\Users\%name%\Documents\VuforiaStudio\Projects\node_modules\cad-import-filters\import_filters\bin\pvsoptimize" -r "C:\Users\%name%\Documents\VuforiaStudio\Projects\node_modules\cad-import-filters\import_filters\recipe\pvsoptimize_%aufloesung%_vuforia.rcp" -p "C:\Users\%name%\Desktop\pvz_tool" -o "%outputname%" "C:\Users\%name%\Desktop\pvz_tool\%input%.pvz" pause
This of course is only a workaround if the file size can't be reduced in any other way.
Cheers
Whity