Sketchfab Forum

Flipped Normals Error When Uploading Models..?


(Hsetterfield) #1

Hello everyone! My first post! :smiley:

Trust my first post to be in the Support forum lol :blush:

I've started developing a VR game and am in the process of creating the models for it. The game is going to be set on a ship in deep space so I've been working on some modular corridors that I can put together when I build my levels.

I've started creating the models in SketchUp and am exporting them as FBX files so that I can do the UV Unwrapping in Maya and then use Maya's handy export feature directly to the Unreal Engine.

They look great in SketchUp and Maya (and aren't showing any problems with the SketchUp Solid Inspector) but when I try and upload them to SketchFab I get an error message telling me that the model has flipped normals:

Is this because I haven't done my UV maps yet and the SketchFab system has a problem with the SketchUp default Material..? Or is this unrelated to that and will cause me problems even after I've done the UV Unwrapping and sorted my textures out..?

I've never done any 3D modelling before so am a complete n00b at this malarky and am pretty much winging it with the help of Google and YouTube lol :blush: :joy: :blush:

Here's a link to my SketchFab thingy, if you look at the models the Straight looks fine, the Dead End has some flickering bits on the end wall and the Turn has flickering bits all over the place! :scream:

Many thanks in advance for any help! :smiley:


(Simon Kratz) #2

Hi @hsetterfield!
It's probably unrelated to uvs or the material. The "flickering bits" are polygons that might have been created during export.
Did you try re-importing the model back into SketchUp and see how it looks?


(Mrchlblng) #3

@hsetterfield, as mentioned by @essimoon, the message you see is not a UV related error but simply a processing warning. We will update our log reporting to make it more user friendly; it simply says that you may have some shading issues i.e. some part could look black instead of correctly lit but those are often false-positive issues and if the shading looks fine, you may forget about the warning.

The flickering issue is a common one with sketchup models and is due to z-fighting with overlapping faces; you may have a look some of our articles

Hope that helps.


(Hsetterfield) #4

I didn't think of importing it into SketchUp! Just downloaded the free trial of the FBX Importer and it imports without any issues so as @mrchlblng suggested it looks like it was a false-positive thing. That's a relief!

Thanks for all of your help guys! :smiley: