topic Select flipped normals only in Maya Forum

Select flipped normals only

keith112 — Thu, 16 Jan 2020 19:36:21 GMT

Hi,

So I'm trying to select faces which have their normals flipped.

Like this example....

I've tried setting the 'Mesh Component Display' to Full seen here and then marquee selecting but it selects the faces anyway.

I've also tried splitting the model in the UV editor and selecting front face...which is close but doesn't work still.

I'm sure I'm doing something silly or maybe it can't be done.

My main goal is to be able to select all the faces on a model which have flipped normals. The example above is very simple but I want to do this on much more complex models.

Thanks to anyone who can help.

Re: Select flipped normals only

damaggio — Thu, 16 Jan 2020 19:53:47 GMT

Try conform normals.

Re: Select flipped normals only

keith112 — Thu, 16 Jan 2020 20:04:28 GMT

Hi,

Thanks for the reply.

Conform definitely would work to flip the UV's on the sphere and maybe other models.

However my main goal is to select all the flipped faces. This is needed for further work down the pipeline.

Its quite long to explain but maybe explaining exactly why I need might shed some light?

Re: Select flipped normals only

damaggio — Thu, 16 Jan 2020 20:07:49 GMT

Okay then, that’s the only solution in Maya.

try it manually.

conform flips the faces .

Re: Select flipped normals only

keith112 — Thu, 16 Jan 2020 20:09:16 GMT

****. Thanks anyway

Re: Select flipped normals only

mspeer — Fri, 17 Jan 2020 00:15:55 GMT

Hi!

@keith112

If the faces only should be selected you can try

1. Select all faces (face selection mode) of the object, then

2. Use Conform as suggested by @damaggio

3. Use Reverse

This will end up with the faces being reversed again, but selected.

Re: Select flipped normals only

keith112 — Fri, 17 Jan 2020 15:11:18 GMT

If it helps here is an example of a model I'd have to work with.

Unfortunately that didn't work. The model remains the same. Ive welded the verts again just to make sure too. The models would be made from SketchUp so I always find they're modelled poorly. i.e- loose verts, flipped normals, double faces.

Re: Select flipped normals only

damaggio — Fri, 17 Jan 2020 15:16:13 GMT

Yes Sketchup models in general are terrible because people don't know how to model and even worse they don't know the right setting to export.

There's no way of fixing this, either model yourself or find a similar model on Turbosquid.

Also try to render as is, maybe it will be okay.

Re: Select flipped normals only

mspeer — Fri, 17 Jan 2020 23:56:25 GMT

Hi!

"Unfortunately that didn't work. The model remains the same."

- Sure, the model will not change, this is what my solution does, only selecting and not changing.

However for the Conform command to be able to find and select the "right" faces a proper topology and connection of the faces of a model is required, which seems not to be the case if it doesn't work, then you have to clean up the model first.

( In most cases it's faster for me to model something on my own, instead of getting a poor model and then to clean it up. )

Re: Select flipped normals only

f_coltro — Fri, 22 Jan 2021 19:36:49 GMT

Hi,

Sorry about the late reply, but I was searching for a solution to this problem, and find it by myself.

Select all the faces from the object with some flipped faces, then go to Mesh Display>Set To Face. Under the tool options select Match face normal. Ta-da! It works for me.

Re: Select flipped normals only

Anonymous — Sat, 23 Jan 2021 10:03:38 GMT

I Have found one solution, That worked for me.

Re: Select flipped normals only

Anonymous — Thu, 23 Sep 2021 17:53:59 GMT

DOOOD. YES.

I've been staring at this all day trying to find the solution...

I seem to rememeber maya had Backfacing as a selection mask at one point, but maybe not...

I saw the Back-Facing selection constraint in the UV editor for none of my shells were reveresed...Didnt think to do a planar mapping and then use that to select the back faces...Might not work for everyone, but perfect for me.

Re: Select flipped normals only

Anonymous — Wed, 29 Sep 2021 07:08:56 GMT

However, for the Conform command to be able to discover and choose the "correct" faces, a good topology and connectivity of the faces of a model is necessary, which does not appear to be the case if it does not function.

Re: Select flipped normals only

scorpiwolfNSV76 — Thu, 25 Aug 2022 02:39:49 GMT

amazing simple, you are my hero 😄