I am trying to render a kind of robot head, for some reason on the top left hand corner there is a black line going across the edge of his head. Is this a lighting problem and is there a way to get rid of it?
Thank You,
Beginner Blender
miniman.blend (600 KB)
The black line is cause by the lamp in the back on the left. (Your left.) It’s obviously too powerful.
For the rest: Ngons on a curved surface… Baaaad! They explain some artifacts around the eyes. SSS… Useless. No visible difference except that the rendering is faster without it. And… The normals are supposed to point outside. All your objects are inside out. You’re very constant but not in the right way.
The distance values for the two Area lamps are too high. Reduce the distance so the line does not reach the main object, then increase the lamp Energy values
thank you very much. That’s exactly what I was looking for.
I was able to fix the problem, very helpful thank you.
Haha thank you for the response, but I’m a serious newbie to 3D in general not just Blender (about 3 weeks of self teaching), so 95% of your response just flew way over my head. Could you please explain in detail a little bit more on what you mean by my objects pointing out, the Ngons, the SSS? I would very much appreciate learning how to fix these problems so that I won’t have them in the future.
Thank You,
Beginner Blender
Faces point in a direction (their normal). You want all the faces pointing in a consistant direction, all pointing outwards or all inwards. If you have a mix it can cause render artifacts.
Subsurface Scattering (SSS) you have enabled. Why ? Is the robot head made out of skin, wax, milk etc, that allow light to pass through them. If not then disable the option.
Ngons are faces with many sides. Try stick to 4 sided or 3 sides in out of the way places to give best clean renders
Thank you very much, but I have one question when it comes to my normals facing the wrong way. I’m still kind of lost, what part of the normals is the wrong way? And how would you sggest me fixing my Ngons? I’m sorry for all the questions, but i very much appreciate the responses.
Thank You,
Beginner Blender
The normals are vectors (an arrow, a direction, whatever) which indicate to Blender where the outside of your object is. When you active their display as shown by Richard, your object must look like a porcupine with cyan/blue spikes. If it doesn’t you select everything and you ask Blender to recalculate the normals with [CTRL N] for a convex object ([SHIFT CTRL N] for a concave object). Note that Blender doesn’t succeed in 100% of the cases to recalculate the normals for complex objects. Sometimes, you need to help it by doing it part by part. Your robot head is an easy object.
Now, for the Ngons, you must redo the eyes. The mesh is way too dense around the eyes. Instead of working with so many vertices, it’s easier to simply use a Subdivision Surface modifier (usually called “Subsurf” modifier). It will take care of smoothing all the edges.
The easiest solution I can think of to fix your eyes is to restart from a half sphere with a Mirror and a Subsurf modifiers. (Note that the Surbsurf must always be after the Mirror or you’ll get problems because the Subsurf “pulls the corners”.) You add a circle where you want the eye to be, you delete the faces behind the circle. You arrange the newly created orbit. I suppose you want it round, so you select all the edges around the hole and you use the Loop Tools add-on to make a circle of them. (I recommend this add-on which often produces better results than what Blender offers with the “To Circle” option. [SHIFT ALT S])
When your orbit is the way you want it to be, you look at the top of the screen to see the number of vertices. Use that number to redo a circle for the eyes. Having the same number of vertices for both the orbit and the circle makes things much easier to avoid the nasty Ngons. 
However, for the flat eyes of your robot, you can turn the circle into a single face, just don’t forget to set the shading to flat. (Select the face, [W] --> Flat shading.)
If you followed my instructions, that should give you something like this:
Now it’s up to you to reconnect the eye and the orbit the way you want. Note that you may need to rotate the circle a bit to align the edges with the orbit. I had to do it here. And, from there, for example, I did this:
I tuned the lights a bit and the Subsurf modifier did the rest.
The file to play with: miniman2.blend (474 KB)
It’s your file, do whatever you want with it.
Last note: I forgot to say that you will see violet edges in the new file. That’s a way to keep sharp edges despite the Subsurb modifier: You increase the Crease. [SHIFT E]. Another way (also used in this file) is called “to tighten the mesh”, i.e. you add a loop cut on one side or both sides from the edge that you want to make sharper. The closer the new loop cuts are, the sharper your edge will look like.
Thank you so much for the help you don’t understand how much I was able to learn and fix. I was able to fully fix up my robot head and now it is without the nasty ngons >.< but before you leave I was wandering how you achieved the smooth kind of curve shape around the eyes in your project I thought it was really cool.
Thank you,
Beginner Blender
That? I didn’t do much. I just selected all the edges around the hole of the orbit [ALT RightClick] and all the edges around the last of the concentric black rings [SHIFT ALT RightClick], then [CTRL E] --> Bridge Two Edge Loops. (For that, you need the same number of vertices/edges on both sides of the “bridge”.) I liked the result so I didn’t rotate the eyes. 2 more edge loops to tighten the mesh and the Subsurf modifier made the whole super-smooth. That’s all. 
So simple yet I would have never thought of it. Thank you so much for your help you can not believe how much I have learned from this. I didn’t even know loop tools existed. This will hopefully let me go on to do bigger and cooler things with Blender.
Thank You,
Beginner Blender