Brand new to Unity, and have to say that I am LOVING learning it!
I have the free Sleek Toon Bot from the assets store using the Standard Assets–>Third Party Controller, so he’s running around my screen like a mad man over a dynamic floor grid that I build at startup. Sweet!
But now I need a couple of walls for my scene so I just tried to do the simplest thing: Add a plane that I can use as a wall. All goes well until I try to rotate it about the X axis. It just disappears! Rotate it on the Z axis? Still visible. Don’t rotate it at all? Visible. Rotate it on the X axis? Disappears.
Before rotation …
After rotation …
I’m sure I am not understanding something fundamental, but I am so new to Unity that I can’t get my head wrapped around what I am doing wrong.
The short answer is that you can only see the surface from the front and not the back because usually you don’t want the player to see the back of a surface. Artists will usually make 3D walls that have surfaces facing outwards on both sides so you can see the wall from both directions.
Since your still learning, I recommend using 2 planes facing away from each other to make the wall. Another thing you could do is use a shader/material that shows both sides of the object it’s drawing, but graphics stuff may be trickier to understand if you’re still learning the basics.
Ahhh!! When I get back to my computer I will flip it around 180 so I can see the “front”. I don’t really need to see both sides, but thanks for the excellent explanation.
This is part of the basis of general graphics around 3D, not Unity.
A 3D polygon have what we call a “normal”, this is a perpendicular vector of the polygon surface.
When the normal is pointing to the camera, you are seeing the front face of the polygon.
In 3D softwares like Maya, 3DS Max, Blender, by default you see front face AND back face of each polygons because it’s easier to edit the model.
In 3D Real-time engines, by default you only see front faces because in most cases, you don’t want the GPU to compute the backfaces of polygons since meshes are usually “closed”.
In a more advanced explanation, the vertexes (dots composing the polygon) have normals and the polygons normal here is an average of the vertexes around it.
For a better understanding of what you are doing with 3D stuffs, I think it’s important to learn the workflow of creating a 3D mesh (even a cube) into a 3D software and the export of it into Unity. (Blender is free).
In 3D Softwares you can displays stuffs like normals.
Wow, the response here has been fantastic. It’s really helping to reduce my learning curve. It makes complete sense that most objects shouldn’t have a “back side” in order to reduce computations. I’ve been watching a lot of “how to” tutorials and reading the Unity docs to accomplish my immediate goals in order to learn and so far haven’t tried to tackle 3D modeling – so this important point has evaded me until now.
I do have blender installed and plan on spending time in there, so this discussion will be rattling around in the back of my brain when that time comes.
