Well, I’ve tried to get into Blender for quite a long time, but could just never get the hang of it. However, I’ve made some strides recently.
Of course, I’ve also encountered a few snags. I’ve heard a lot of talk about the “normals” of faces and how they have a tendency to get screwy. No tutorial I’ve read yet actually explains what normals are, nor why they’re such troublemakers. Could anyone help with that?
Also, why do some people seem to have such a disdain for using triangles as opposed to quads?
And finally, I rendered this simple scene, which is of a cube subdivided a few times. No other modifications were made, other than changing the material to add a little more contrast between it and the background:
Sorry if you’ve seen these things many times before, but I haven’t had much luck elsewhere.
A normal is a line that’s perpendicular to a surface, another line, a vertice… basically a normal shows which way a face/vertice is facing. In the mesh tools there are 2 buttons, ‘Draw Normals’ and ‘Draw VNormals’, pressing these causes Blender to draw the normals for the faces/vertices on your model.
Triangles tend to cause problems with subsurf, which is why most people try to use quads whenever possible.
In your image it appears that some of the faces are facing the wrong way. This can be corrected by selecting all the faces and pressing Ctrl + n to recalculate normals outside.
The black marks may also be due to smoothing errors if you’ve “set smooth” on the object. The algorithm is trying to smooth the sharp corners and confusing the renderer. Try turning on the Auto Smooth button in the F9->Mesh panel.
Your worthless factoid of the day: “Normal” is a fancy-smancy term mathematicians use to mean “at a ninety degree angle to”
Triangles not only tend to screw up subsurf, they also interfere with the “edge loop” tools. When the tool makes an edge loop, it comes to a screeching halt when it runs into a triangle.
As a matter of interest there is no reason, ever, to use smoothing on a simple cube or any shape with flat sides and sharp edges. Set Smooth is for curved-surface objects and Auto Smooth is for objects with combined curved surfaces and sharp edges (like a cylinder).
