Annoying modeling bugs that never get solved...

[mahri726]

I have some problems with Maya 2013. In normal mode, the tower has weird shadows. In smooth shaded mode, a broken line appears. If I delete it, the edge beneath it gets the same effect.

Another anoying problem is in the case of corner in shaded mode. I deleted some edges before, in normal mode it looks allright, in shaded mode it looks like this. In the past, I reconstructed an entire 3D head because of this problem. It's like a transmisible skin (polygon) desease, to give you a more exact description of how did I cure it then.(a very much time consuming approach) So...this is an example: you have a plane, divided in several pieces. A polygon in the center of the plane has a different shading than the others, and forms a nasty edge around in shaded mode . You delete the adiacent polygon, extrude the edge of the ,,ill'' polygon, and use the merge vertex tool to merge the two vertices to fill the gap. The nasty edge gets larger untill I fill the entire mesh and desapears. 

Firstly, how to solve the first problem, and secondly, how to solve the second?

[whisper1]

The first problem sounds like overlapping objects. Might be something else. It is hard to remotely diagnose some problems.

The second one (with the odd geometry lines) looks like what happens when you have an object selected and accidentally press 2 or 3 on the keyboard. Select the object and press 1. See if that fixes it. (I have no idea what advantage or function the 2 & 3 are supposed to provide in Maya's messed up history--their affect does not change how the objects render.)

[n8skow]

Looks like an issue with the geometry - like you have several verts in one spot that are not merged.