Some mesh files load into Rhino 7.2 much slower than other mesh files

Rhino Rhino for Windows
1

I have loaded two 3D Studio (.3DS) files from the Internet. They have similar size, but one of them loads in Rhino 7.2 much slower than the other. These files are similar - they are made entirely of meshes, so their loading time should also be similar. During the loading my old laptop did not consume much CPU RAM or video RAM. Apparently one CPU core was doing all the work.

Ford F150 pickup truck model loads in 3 seconds. file size = 13MB. source: https://archive3d.net/?a=download&id=6224dc81

Semi truck with trailer model loads in 126 seconds. file size = 16MB. source: https://archive3d.net/?a=download&id=f91846f1
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Trench mortar model also loads slowly - in 2 minutes. file size = 28MB. source: https://archive3d.net/?a=download&id=1cd052e4

2

Looks like the semi has about twice as many vertices and faces as the pickup.

-Pascal

3

I agree, that seems slow.
I tested the Semi and it has 221 meshes and 800K faces which isn’t much these days.
So I don’t know what Rhino spends those 75 seconds on (i7 10700 here).

And @pascal even though it has twice the amount of vertices it should not take 20-40 X longer to load, do you think? (I didn’t test the F150, I just used Andrews 3sec data there)