If this is addressed at a later video just let me know, but I figured I'd ask before I forget.
I understand the purpose of modifying the way the subsurf affects the shape, when we removed faces in the back/top of the teeth and eyebrows.
But is there any other reason to remove hidden faces or geometry? Like rendering performance, or something else? I've noticed it being done in other models but not sure why.
And a second part to the question: when different parts of mesh intersect (in the same object or separate pieces), does it make a difference to leave the hidden geometry or not? What is the best practice?
Thanks for any insight!
In this case it is just to keep these areas from rounding out with the subsurf modifier.
There will be times when deleting faces will be for performance purposes, when modelling game assets for example.
With intersecting meshes, it doesn't matter if the geometry is hidden, again unless its for performance, a very large scene is another example.
It really doesn't matter, unless the intersecting geometry has faces sharing the same 3d space plane axis, Blender wont know which face to display and try displaing both which causes weird shading known as z fighting.
It comes down to the shape you are modeling, and your own OCD preferences.
And you will develop OCD's when you have been modeling longer.
Yeah, like Adrian says.
If you can remove 'hidden' Faces that aren't 'doing anything', remove them, but don't worry if you (accidentally or out of laziness or so) leave them.
I don't think it will make a difference in the actual Rendering, but in loading the model and triangulation, it might be a minimal difference.
A Cube Mesh, for instance is like a list of 8 Vertices (and at least their Positions), 16 Edges (and how they are connected to the Vertices) and 6 Faces (and...). Removing one Face, that is inside another Mesh, for instance will make that into a list of 8 Vertices, 16 Edges and 5 Faces. That list is shorter and will take less Memory...and one less Face to Triangulate...The savings you will be able to make in complex Models and Scenes will usually be neglectable (removing NGons might be more of an advantage, but unless you are modeling for Games, you shouldn't worry too much about whether or not to remove a Face.
That makes total sense! Thanks for the breakdown guys, I appreciate it!