Surface orientation on imported solid breps rhino 7

hafner-johannes · September 23, 2020, 1:33pm

Hello,
guess this is just a glitch in rhino 7 which will probably be resolved in one of the next updates, in any case for the record:
I’m experiencing weird issues with the orientation of surfaces on imported solids (from solidworks, both as .stp and .sldprt) in rhino 7.
First noticed this since we use a grasshopper definition to orient the largest surface of a brep on the xy plane and suddenly some objects ended up below zero.
Showing the backface color confirms this:

explode + join fixes this, but is not practical for multiple objects and deconstruct brep + join in grasshoper doesn’t seem to fix it reliably, checking for volume center < 0 and rotating them.

Helvetosaur · September 23, 2020, 2:03pm

Do you have a sample you can post here?

I wouldn’t say this topic belongs in the Hardware category - I am going to move it to the Serengeti section.

hafner-johannes · September 23, 2020, 2:07pm

Sorry for the wrong category, hier is the .sldprt and the rhino7 .3dm
dogbone_torture.3dm (165.7 KB) dogbone_torture.SLDPRT (131.9 KB)
initially thought it might be a solidworks issue, but rhino 6 seems to open it correct.

Helvetosaur · September 23, 2020, 2:12pm

Ooh, yeah, that is interesting, it’s closed yet some of the surface normals are flipped… Explode/Join in normal Rhino fixes it but that definitely looks buggy. @chuck this may be in your wheelhouse…

chuck · September 23, 2020, 4:40pm

Not me, but I’ll pass it on. Thanks.

RH-60639 Solidworks import has inconsistent normals

Normand · September 25, 2020, 7:11am

Hi All
Just wanted to mention, that I’m seeing this in V6 as well - but I guess that it’ll be fixed for V7 only. The parts are closed polysurfaces, but some normals are flipped - really weird! These were imported directly from a SWX assembly.
two parts imported from SWX.3dm (932.2 KB)
-Jakob

norbert_geelen · September 25, 2020, 8:31am

This happens from time to time with imported geometry, especially when naked or tolerant edges are involved, regardless of what version of Rhino is used (beginning from Rhino5).

wim · September 25, 2020, 10:14am

Hi Jakob -

I suppose that if you have the original file, we could attach that to the YT item as an extra example.
-wim

dyzajn · November 11, 2020, 1:56pm

I have the same problem in RH7, some surfaces are flipped (red surface). I am pretty sure the solids are watertight. In RH6 this didnt happened at least what I can recall. I recently upgraded Solidworks from 2015 to 2020. I cannot open SW2020 in RH6. Would be nice to have possibility to open SW2020 in RH6.

wim · November 11, 2020, 2:03pm

Hi -

Item RH-60639 is still open.
If you can post the original sldprt file, we can add that as an extra example in that item.

With Rhino 7 being out, only severe crashing issues will be fixed in Rhino 6.
-wim

dyzajn · November 11, 2020, 2:12pm

I can post something universal, not designed for my client… e.g. headset:
headset-top.SLDPRT (164.9 KB)

wim · November 11, 2020, 2:45pm

Thanks, I’ve added that to the tracker.
-wim

dyzajn · January 5, 2021, 1:53pm

Hi, with latest rhino 7 evaluation version, i am trying to import solidworks 2020 (*.sldprt) file into rhino and it seems there is still a bug in translator, The red surfaces are flipped:

Opening the same file saved from solidworks to STEP and opening in rhino works fine:

dyzajn · March 18, 2021, 3:55pm

After installing 7.4 service release, there is still bug in importing/opening native solidworks file. The same file exported to STEP is ok, but SLDPRT has always switched some normals. Thats pretty annoing especially with complex bodies.

Using Solidworks 2020 SP 5 to Rhino 7.4.21067

I like when new versions of software have new functions. But what I do not like more is that old functions are not working the same way as before. Unfortunately, from version to version, I have bad feeling about reliability of Rhino. Rhino 5 was really great and stable, never crashed, veretyhing worked fine. 6th was sometimes crashing, many bugs in drwaing lines, localization etc. Please, dont go the way as other software vendors, when last servicepack before new release is finally stable and ready to use. I dont mind to wait another year for new version.