Hello All,
I was modeling a glass goblet and when i tried to render it, i got this really weird pepper looking model. I played with all the refraction settings and transparency settings but nothing works. Any suggestions?
P.S. I just started using Blender a week ago, so forgive me if the issue is obvious. 
Overlapping faces. Go into edit mode, select all the vertices, then hit “Rem. Doubl” in the editing(F9) panel.
thanks! Can you tell me a little more about overlapping faces?
At some point you duplicated the whole object without realising, so you had faces occupying the same space. When you render, Blender has no way to tell which faces are in front and which behind, so you get that distinctive chequerboard shading.
After you do “Remove Doubles,” and if it doesn’t completely solve the problem, look over your geometry very carefully. You might find things like “interior faces” (my term), which are “inside” the object but don’t need to be there, and you might find “intersecting” faces where one face protrudes through another but there’s no connection between them. This is the sort of thing that can confuse the renderer.
Also, after doing all the cleanup you can, “recalculate normals outside.” The normal-vector, as you probably know, is an imaginary vector that points “out of the front side” of the face. You know where “the front side” is supposed to be, but Blender’s just a piece of computer software. This step will recalculate the orientation of all of the surface normals, so that they do point “outside.”
Finally… I routinely go into Edit mode and “select all.”
