Some of my Blender model's faces are invisible even if I recalculate normals in blender

Problem:
I imported my mesh from blender to ROBLOX as a obj, and noticed there were some invisible faces. I tried recalculating all the face’s normals after, but that didn’t seem to work either.

Question:

  • How do I go about avoiding this from happening in the future?
  • Am I able to fix this now? If so, how?

Sometimes you just have to flip them manually.

Go to overlays and toggle face orientation.

Screen Shot 2020-09-30 at 7.06.34 PM

Inverted faces will be highlighted in red.

Screen Shot 2020-09-30 at 7.06.49 PM

2 Likes

I tried this, I saw some faces that were red and flipped them all manually. For some odd reason however, holes still show up in my model. Thank you for trying to help however.

If you are using a plane as a starting mesh, then you need to use the Solidify modifier under the modifier tab.

I did this, but now I am having trouble flip the normals because some of the red surfaces are inside of the faces, and sometimes when i try flipping those faces it will pop out new red spots.

If those faces are planes, which means, that dont have thickness, one of the 2 sides will be facing the wrong direction, the solution is

  1. Solidify modifier
  2. Extrude that face, and then recalculate normals again

Also, roblox sometimes bug and even though in Blender faces are good, in roblox can be facing the wrong way, and it can be really annoying sometimes, so make sure that atleast, its not your fault, and in case blender its fine but roblox isn’t, just find another way to fix it.

And also consider making meshes with good topology, your mesh definitely is a “Mess” I know it is meant to be like this, but it is hard for Blender to do things correctly with this complex shapes, always try to keep square faces (4 vertices) and also in case nothing fix it, separate the mesh in more “simple” shapes, to the faces thing, and then, join them together again.

Good topology:

Bad toplogogy:

Topology is a hard term and usually it takes time and experience to model in a clean and good way for modifiers.