Author Topic: Reversing Normals  (Read 675 times)

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Offline richardfunnell

Reversing Normals
« on: December 17, 2019, 05:28:02 pm »
It would be really, really helpful to be able to reverse surface normal direction on a part :)
I often receive geometry from partners who can't control the surface normal directions (exporting from CAD) where a set of surface normals are flipped which leads to rendering issues down the line. Re-calculating normals doesn't help, and the only solution is to re-export the model in a different format and hope for the best when re-importing. In a worst case scenario the part can't be remodeled so I don't have any good options to fix this.
This isn't a huge pain, but when it happens I simply don't have an easy fix. Unifying normal directions would be a huge help!

Offline mafrieger

Re: Reversing Normals
« Reply #1 on: December 18, 2019, 02:34:11 am »
+1

Offline INNEO_MWo

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Re: Reversing Normals
« Reply #2 on: December 18, 2019, 09:21:06 pm »
+1

Online Eric Summers

Re: Reversing Normals
« Reply #3 on: January 03, 2020, 07:57:08 am »
+1

Offline Søren

Re: Reversing Normals
« Reply #4 on: January 06, 2020, 10:46:18 am »
Is this about fixing inconsistent normals (i.e. normals do not point the same direction on some subset of the part) or reversing all normals?

Søren

Offline richardfunnell

Re: Reversing Normals
« Reply #5 on: January 06, 2020, 10:59:39 am »
Hi Søren, long time :)

My biggest issue tends to be when I have inconsistent normal directions on a single body from CAD imports; areas that contain inverted patches lead to issues with texture mapping and geometry nodes. Since traditional CAD has limited control over this upon export (other than re-building) it can be an extremely frustrating experience.

I haven't needed to reverse all normals, but that may be something that others have experienced.

Offline richardfunnell

Re: Reversing Normals
« Reply #6 on: January 07, 2020, 09:39:59 am »
Just remembered another area where reversing the normals on the whole body would be great, in this case it was an issue when trying to use rounded corners. Normals pointed inwards leads to strange results, and I don't have a way to fix it :/

Online Eric Summers

Re: Reversing Normals
« Reply #7 on: January 08, 2020, 09:29:00 am »
What I ran into that made me wish I could reverse normals was related to fuzz. I had multiple surfaces created in SolidWorks that were going to have the same material applied to them. When I got into KeyShot and applied the material with fuzz, some of the surfaces had the fuzz going in the opposite direction (see attached mockup image). Because the fuzz wasn't going the same direction on all the surfaces and I couldn't just rotate the surfaces 180° (due to the origin of the part and the fact that all the surfaces were at compound angles to the standard planes), I had to unlink materials and ended up with two versions of the same material. One version had the fuzz length positive and the other negative so they would be going the same direction. It would have been nice to reverse the normals to have only one material.

Offline mattjgerard

Re: Reversing Normals
« Reply #8 on: January 09, 2020, 07:37:01 am »
This is a common quick fix when having texturing problems in cinema 4d when importing cad based files and tesselating complex cad geometry when it comes to smooth phong shading. I had a macro setup that would select all polys, the it would run the "Align Normals" command to get them all pointing the same way (in or out) then reverse them if needed. Worked 99% of the time. Was very handy for troubleshooting purchased models.

Offline mafrieger

Re: Reversing Normals
« Reply #9 on: January 17, 2020, 10:54:52 am »
wow, this seems to be integrated in latest 9.1 beta
only 4 weeks from wish to feature :-)

Quote
Changes from KeyShot 9.1.69
- Added option to flip normals for Fuzz

https://www.keyshot.com/forum/index.php?topic=25507.msg107379#msg107379

Offline richardfunnell

Re: Reversing Normals
« Reply #10 on: January 21, 2020, 06:34:34 pm »
wow, this seems to be integrated in latest 9.1 beta
only 4 weeks from wish to feature :-)

Close, but not exactly :) This is indeed very nice for the Fuzz geometry node, but it only applies there. My request (echoed by a few) is for a way to unify the geometry normals of the underlying geometry.

Offline Will Gibbons

Re: Reversing Normals
« Reply #11 on: February 02, 2020, 08:53:23 am »
This is one of my top requests (recently submitted to Derek along with a handful of others). When I ran into this most recently, it was: 1) when I needed rounded edges on a speaker mesh. The rounded edges didn't work well, so I had to manually fillet 7,000+ fillets in CAD and re-import... that cost me about 1 day of productivity. 2) When clients have cad with fillets, often times the normals on the filleted part of the body face inward while the rest face outward. Re-calculate normals as Richard mentioned isn't any help. It's good for 'smoothing' low-poly mesh data, but on CAD/NURBs based geo, it doesn't help.

If the Normals tool got the following, it would be great:
1) Align Normals
2) Flip Normals
3) Smooth Normals with angle slider (like we currently have)

This seemingly small feature could lead to people who use KeyShot in a production setting saving thousands of dollars per quarter. Not exaggerating at all.

Offline mafrieger

Re: Reversing Normals
« Reply #12 on: March 04, 2020, 07:04:59 am »
+1 for the real fix / feature (was wrong when thinking it's already there...)