OMG Talk about creating Flipped normals

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here is my final EEVE and CYCLES render of my little scene. It only took two hours because (and that’s what the next lesson was for I rekon).
While extruding the little overhangs I thought I would be cleaver. rather than going UP and hiding the little lips underneath said overhang, I thought “Okay, lets go DOWN and then select two opposite edges and create a FACE”
This looked great and I was impressed with myself greatly, UNTIL I turned on Back Face Culling, and there it was, all my pillars where showing through the roof overhangs,nope. in fact it was because the faces i had created over the extrudes where flipped. No idea why but they where.

I used the next tutorial on normal’s which I had watched already a few days before to refresh how to fix this…
Great cleaver challenge,You knew we would mostly make this error or similar occur in extruding edges alone rather than actual faces,
By the time I opened the Mess.Blend file for the next lesson. I fixed that in about a minute LOL.

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Lesson%2025%20Mid%20section%20challenge%20Farm%20CYCLES%20RENDER
Lesson 25 Mid section challenge Farm CYCLES RENDER.jpg1920×1080 161 KB

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https://youtu.be/1w0avRrCmcA video 1

https://youtu.be/o602e_Ha1qY video 2

This is how I created those flipped normals. Ironicaly I created the video thinking I was being cleaver at the time ROFL!"

The second clip did NOT create a flipped normal as I extruded the edges down then made the face.
The first video created a fliped normal when i extruded the face that was generated during edge extrusion. I am guessing such faces are BORN with no specific direction initially and HAVE to be assigned. I think this should be added to the instruction tutorial at some point where lots of extruding takes place.

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So, video 1 you

  1. created a new face by extruding in the pos-Z
  2. Pressed [Esc] (I suspect) which set the extrude distance to 0 (zero)
  3. Moved the extruded face in the neg-Z

Which means, in step 3 you pushed your geometry through itself and created a box with all its normals reversed.

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aha. so its possible to avoid it then ?

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Absolutely, in this particular case the solution would have been to keep the extude distance and slide the new face over to the roof.

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in order to do that however I would have to run backface culling as i go i guess, to pick out or re arrange on the hop. preventing finding 20 or so faces at the end of a build,