Blender Make single face two sided

[Nordscape]

Hello. I have a single faced "fence" which I want to make double sided. I have found a way to do this by activating MSFS parameters in Blender, but that clears out my imported textures.

In the image below I want to keep the details, but they are removed as soon as MSFS parameters are activated.

Is it possible to make a single face double sided in Blender "natively" so that is possible to keep the imported textures?

...If not; is it possible to activate MSFS parameters without clearing out the imported textures, or reactivate them with the msfs parameters activated?

 

[Nordscape]

Sorry, never mind. Unticking "backface culling" is the solution.

 

[GaryGB]

Hi Vetle:

As you probably know, most FS 3D models are single sided and do not have a Face inside to map texture Materials onto.


That lack of extra interior geometry and UV mapping saves on rendering work and Texture Vertices (aka "T-Verts").

I am assuming you already use a Sketchup exporter that disables any such reverse Faces, or you use MCX' Option to do this ?

https://www.google.com/search?q=site:+www.fsdeveloper.com+MCX+Option+bacface+culling&client=firefox-b-1-d&hs=GMWp&sca_esv=53f9ef8ad52bf813&biw=1200&bih=586&ei=vaW1abbmItSup84P1rbmyAc&ved=0ahUKEwj2uP_B_5-TAxVU18kDHVabGXkQ4dUDCBM&uact=5&oq=site:+www.fsdeveloper.com+MCX+Option+bacface+culling&gs_lp=Egxnd3Mtd2l6LXNlcnAiNHNpdGU6IHd3dy5mc2RldmVsb3Blci5jb20gTUNYIE9wdGlvbiBiYWNmYWNlIGN1bGxpbmcyBxAhGKABGAoyBxAhGKABGAoyBxAhGKABGAoyBRAhGKsCMgUQIRirAkir3QFQ5B1Y09kBcAJ4AZABAJgBgAKgAesvqgEGNC40OC4xuAEDyAEA-AEBmAI3oALeMcICChAAGLADGNYEGEfCAgsQABiABBiRAhiKBcICDRAuGIAEGEMY5QQYigXCAgoQABiABBhDGIoFwgIEEAAYA8ICDhAuGIAEGLEDGNEDGMcBwgILEAAYgAQYsQMYgwHCAhEQLhiABBixAxjRAxiDARjHAcICFBAuGIAEGLEDGIMBGMcBGI4FGK8BwgIOEC4YgAQYxwEYjgUYrwHCAggQLhiABBixA8ICCBAAGIAEGLEDwgIQEC4YgAQY0QMYQxjHARiKBcICBRAAGIAEwgIMEAAYgAQYsQMYChgLwgIJEAAYgAQYChgLwgIGEAAYFhgewgILEAAYgAQYhgMYigXCAggQABiABBiiBMICBRAAGO8FwgIFECEYnwXCAgUQIRigAcICCBAAGKIEGIkFmAMAiAYBkAYIkgcGNi40OC4xoAf1iwKyBwY0LjQ4LjG4B9AxwgcJMC4zMi4yMS4yyAecAYAIAA&sclient=gws-wiz-serp


IMHO, when one must use double-sided Faces, it is desirable to have already created them in Sketchup, rather than Blender.

Creating them in Blender is a more complex multi-step process, and makes a case for NOT using Blender Back-Face culling.


KatsBits tends to have good tutorials compared to many convoluted newer tutorials on the web; IMO, this one is easier to follow:

https://www.katsbits.com/codex/double-sided-materials/

https://www.katsbits.com/site/double-sided-faces-different-materials/


A FSDEV thread on this topic from 2024:

https://www.fsdeveloper.com/forum/threads/removing-double-sided-faces.76400/post-927450

"Blender 2.8+ renders surfaces double-sided by default."

BUT...

"Important: back-face culling is typically the default state surfaces are process(-ed) and rendered (in), thus two-sided surfaces, surfaces appearing solid front and back, are essentially a post-processed effect – a given original (and culled) surface and associated properties are duplicated and flipped to produce the two-sided (simple) effect. In this context neither side acts independently of the other, so they can appear incorrectly shaded or shadowed (the back-side of a leaf should be shaded but is often drawn fully lit per the front-side). This latter problem can be addressed using a double-sided mesh."

Not surprisingly, both Sketchup and Blender make double-sided Faces by default (unlike other 3D modeling apps).

An important take-away for FS scenery making / rendering: via Direct-X, Clockwise vertex winding creates "Front Faces".

And for FS scenery making / rendering: via Direct-X, Counter-Clockwise vertex winding creates "Reverse / Back Faces".


AFAIK, this may impact behavior of Polygons used for Terrain, whether Terra-forming or draping imagery, excludes etc.

So, IIUC, we should always place vertices for single Polygons in a Clockwise vertex winding direction.

And, IIUC, we should sequentially place vertices for alternate 'stacked' Polygons in a Counter-Clockwise winding direction.

GaryGB

 

[Nordscape]

Hi Vetle:


I am assuming you already use a Sketchup exporter that disables any such reverse Faces, or you use MCX' Option to do this ?

https://www.google.com/search?q=site:+www.fsdeveloper.com+MCX+Option+bacface+culling&client=firefox-b-1-d&hs=GMWp&sca_esv=53f9ef8ad52bf813&biw=1200&bih=586&ei=vaW1abbmItSup84P1rbmyAc&ved=0ahUKEwj2uP_B_5-TAxVU18kDHVabGXkQ4dUDCBM&uact=5&oq=site:+www.fsdeveloper.com+MCX+Option+bacface+culling&gs_lp=Egxnd3Mtd2l6LXNlcnAiNHNpdGU6IHd3dy5mc2RldmVsb3Blci5jb20gTUNYIE9wdGlvbiBiYWNmYWNlIGN1bGxpbmcyBxAhGKABGAoyBxAhGKABGAoyBxAhGKABGAoyBRAhGKsCMgUQIRirAkir3QFQ5B1Y09kBcAJ4AZABAJgBgAKgAesvqgEGNC40OC4xuAEDyAEA-AEBmAI3oALeMcICChAAGLADGNYEGEfCAgsQABiABBiRAhiKBcICDRAuGIAEGEMY5QQYigXCAgoQABiABBhDGIoFwgIEEAAYA8ICDhAuGIAEGLEDGNEDGMcBwgILEAAYgAQYsQMYgwHCAhEQLhiABBixAxjRAxiDARjHAcICFBAuGIAEGLEDGIMBGMcBGI4FGK8BwgIOEC4YgAQYxwEYjgUYrwHCAggQLhiABBixA8ICCBAAGIAEGLEDwgIQEC4YgAQY0QMYQxjHARiKBcICBRAAGIAEwgIMEAAYgAQYsQMYChgLwgIJEAAYgAQYChgLwgIGEAAYFhgewgILEAAYgAQYhgMYigXCAggQABiABBiiBMICBRAAGO8FwgIFECEYnwXCAgUQIRigAcICCBAAGKIEGIkFmAMAiAYBkAYIkgcGNi40OC4xoAf1iwKyBwY0LjQ4LjG4B9AxwgcJMC4zMi4yMS4yyAecAYAIAA&sclient=gws-wiz-serp

Thanks Gary. I am not using any exporter at all. I import the model with the Sketchup save file directly into Blender - which have been working quite well actually. I ensure that all faces are correct by using the "untextured view" in Sketchup before the final save.

IMHO, when one must use double-sided Faces, it is desirable to have already created them in Sketchup, rather than Blender.

Creating them in Blender is a more complex multi-step process, and makes a case for NOT using Blender Back-Face culling.


KatsBits tends to have good tutorials compared to many convoluted newer tutorials on the web; IMO, this one is easier to follow:

https://www.katsbits.com/codex/double-sided-materials/

https://www.katsbits.com/site/double-sided-faces-different-materials/


A FSDEV thread on this topic from 2024:

https://www.fsdeveloper.com/forum/threads/removing-double-sided-faces.76400/post-927450

"Blender 2.8+ renders surfaces double-sided by default."

BUT...

"Important: back-face culling is typically the default state surfaces are process(-ed) and rendered (in), thus two-sided surfaces, surfaces appearing solid front and back, are essentially a post-processed effect – a given original (and culled) surface and associated properties are duplicated and flipped to produce the two-sided (simple) effect. In this context neither side acts independently of the other, so they can appear incorrectly shaded or shadowed (the back-side of a leaf should be shaded but is often drawn fully lit per the front-side). This latter problem can be addressed using a double-sided mesh."

Not surprisingly, both Sketchup and Blender make double-sided Faces by default (unlike other 3D modeling apps).

An important take-away for FS scenery making / rendering in Direct-X, Clockwise vertex winding creates "Front Faces".

And for FS scenery making / rendering: via Direct-X, Counter-Clockwise vertex winding creates "Reverse / Back Faces".


AFAIK, this may impact behavior of Polygons used for Terrain, whether Terra-forming or draping imagery, excludes etc.

So, IIUC, we should always place vertices for single Polygons in a Clockwise vertex winding direction.

And, IIUC, we should sequentially place vertices for alternate 'stacked' Polygons in a Counter-Clockwise winding direction.

GaryGB

I am not too familiar with the issues you mention above, so I cannot relate to it all that well. With that said, unchecking the "Backface" culling in Blender after making the model and texturing in Substance painter kept the textures as they were made within substance paint, and the show both the back and front side within the sim - so to me it seems that that simple unchecking of that box worked quite well