See-through faces using custom mesh

[Octal Forty]

I am using Blender 2.35 for mesh creation/exportation.

I followed the castle tutorial on blender3d.org, and, referencing q & a's on this forum, was able to import my new castle to my landscape.

However, my castle has missing edges, meaning, if I face an image, the face facing me appears translucent.

My mesh consists of 3 separate meshes and materials. A separate mesh and material for the spires (the material was merely defined as a red color), each tower (the material here is a beige color), and the castle front wall and surronding walls (each a material of a light gray color).

One thing I did here was box select the three meshes and ctrl-j'd them into a single mesh (I didn't want to manually align each mesh). Was this the right approach?

I don't have a website or else I'd post screenshots and meshes. I guess a description will have to do. Blender developers, experienced Ogrians, any ideas?

[edit] added a question mark to the end of a sentence which implied a question, and, in fact, was a question. Mental note: re-read posts before posting.[/edit]

[temas]

Sounds like you probably want to check your normals.

[:wumpus:]

You need to check your vertex winding (clockwise versus anticlockwise), normals don't affect backface culling only lighting afaik

[reimpell]

However, my castle has missing edges, meaning, if I face an image, the face facing me appears translucent.

As temas already said, this is probably an issue with your normals. Select the mesh, go to edit mode, select all, Mesh->Normals->Recalculate Outside. You may also deselect "Double Sided" in the Mesh Editing Buttons to have a visual feedback if normals point to the wrong side. Double sided faces are not supported since they promote a waste of resources and are rarely used intentionally. If you need a double sided faces, select the face, duplicate it and flip the normal.