Why the iges input result is polysurface?

testfff.igs (1.4 MB)

Hi all,
I have a iges file, see the attached file, I check its data format only has
one surface(144/142 iges system), but when I import to Rhino, its result
is polysurface? how to avoid this situation? how to set the parameter to repair ?
thanks

Hi,

your knotvector of your surface is extremly weird! You have a lot of duplicate entries in the middle of it which can indicate kinks (or continuity of lower order). Rhino may interprets this at somepoints as a wanted break:

128,468,60,6,6,1,1,0,0,0,0,0,0,0,0,0,0,4.5938066e-3, 1P 1
4.5938066e-3,4.5938066e-3,4.5938066e-3,4.5938066e-3, 1P 2
4.5938066e-3,1.7592506e-2,1.7592506e-2,1.7592506e-2, 1P 3
1.7592506e-2,1.7592506e-2,1.7592506e-2,3.0591206e-2, 1P 4
3.0591206e-2,3.0591206e-2,3.0591206e-2,3.0591206e-2, 1P 5
3.0591206e-2,4.3589906e-2,4.3589906e-2,4.3589906e-2, 1P 6
4.3589906e-2,4.3589906e-2,4.3589906e-2,5.6588606e-2, 1P 7
5.6588606e-2,5.6588606e-2,5.6588606e-2,5.6588606e-2, 1P 8
5.6588606e-2,6.9587305e-2,6.9587305e-2,6.9587305e-2, 1P 9
6.9587305e-2,6.9587305e-2,6.9587305e-2,8.2586005e-2,

Not to speak of your heavy surface data, and your horrible outline (but thats another topic)

You may just simplify your surface data :slight_smile:

I agree with @TomTom, but if you must have this in without splitting you can try running the Rhino command CreaseSplitting and turn it off before importing the IGES.

1 Like

Many thanks, I already solve my splitting surface trouble (use CreaseSplitting).