I´ve been sucessfully using inkscape for technical illustration for arround a year know. However today I thougt for a while I might have to switch back to illustrator because opening uge 3D-exports (more than 50.000 nodes) made inscape crash at first.
However, I finally found a way to get going again, that I would like to share with you.

This is what I do in SolidWorks:
1. I export a line drawing as a PDF-file.
(Opening those files in Inkscape is usally no problem as long you have less than 20.000 nodes...)

This is what I do with inkcape when I have huge PDF-files to open in inkscape:
1. Before I drag&drop the PDF onto the canvas I switch to "outline" mode. (Very important!)
2. Don´t try to move it yet.
3. Klick on the object. In my case its usally a uge path, consisting of around 50.000 nodes.
4. Simplify the path Ctrl+L
5. Break apart Shift+Ctrl+K (10th thousands objects...)
6. Group all of them Ctrl+G
I found out, ones the orginal huge path is broken apart and all objects grouped, Inkscape is back to normal operation speed.
I really was just about to give up on inkscape when it comes to importing such uge linedrawings.

Hope it will be helpful info for some of you out there.

Thanks for the tip