Colocated Vertices


I hope that this tutorial will help you to understand what is meant when you try to compile your project and get the "Found colocated vertices within triangle" error message.

By definition, a polygon is a surface made from three points in 3d space and having three edges. If two of the three points have the same coordinates then they are colocated and the poly only has two edge faces because the length of the edge between the colocated points is of zero length. So this violates the definition of a poly and thus generating the error message when compiled.

For the sake of simplisity, I have made a single poly.



When I move one point to the location of another within that poly, I have now made a poly with colocated verticies.



When I compile I will get the error message.



Note the coordinates of the colocated vertices. They are the same.



The generally accepted method of eliminating colocated verticies is selecting all of the points withn the offending part and weld them.



While this probably works 99% of the time, I have run into situations where this doesn't work.



Notice that all I am left with after the weld is just two points and no faces so I no longer have a poly defined.

Lets backup for a minute and look at two other alternatives.

The first is to delete the offending poly altogether. In a dense mesh just finding it can be difficult, but it can be done. The bad poly will appear as just a line in any view when selected.

The other method is to move one of the colocated points and therefore they will no longer be colocated.

But how do I know which one to move, you ask? Ahhhh... that is in the error log that makemdl.exe generated when you tried to compile before. Remember those colocated coordinates from the error log. They are in meters. Convert the coordinates to your scale. In my case since I am using decimal feet I multiply them by 3.28
and here is what I get. ( 1.828800,-1.524000,-0.000050) = ( 6.000, -5.000, 0.000 ). When I go to these coordinates in Max I find the two colocated vertices. Select on of them and watch the vertex selected note in the panel. It reads "Vertex A Selected". Click on there again and it should read "Vertex B Selected". I am using A and B as yours will probably differ. Once you have selected one move it. If you have moved the wrong one, undo and select the other and move it. Now you no longer have colocated vertices and the poly will meet the definition.


This concludes this tutorial. I hope it has helped you to understand what is happening when you get this error.