Black Lines showing up on edges

[AdamZadig]

Anyone else know why this happens. 

Example: Large mesh plane, divided into 4 equal texture faces. 
When camera draws out a thick black line shows on the joining edges. In the photo attached, the black line shows at all distances. 

So my real question is about unwrapping in Blender. 

Is it better to always leave a margin?
In the below example there was no margin when unwrapping the 4 individual faces on the floor. 

 

 

[arton Rotaru]

51 minutes ago, AdamZadig said:

Is it better to always leave a margin?

The answer is to this question is: Yes!
There will be color bleeding due to Mip Mapping, when smaller versions of the textures are displayed.
 

[Chic Aeon]

Along with that YES, if you look closely at your baked texture you will often see where the problem lies.  Even with some padding there are times where you will have black lines because of the way something has been baked.  ALSO if you have one object "pushed into" another object (like a chair leg pushed into a round stool for example) rather than EXTRUDED (so sharing the same vertices) you will almost always get a black shadow line. 

 

In your example it would be better perhaps to bake at a larger resolution so that you don't need four sections for a single plane. 

[Kyrah Abattoir]

16 pixels of padding is a good generous value.

Why?

It gives 8 pixels for each neighbor island, which when zoomed out becomes, 4 pixels and then 2 pixels, so the seams don't just crack open.

[AdamZadig]

Putting it to the test and yep, adding margins when unwrapping is giving a much better result. 

[AdamZadig]

52 minutes ago, Kyrah Abattoir said:

16 pixels of padding is a good generous value.

Why?

It gives 8 pixels for each neighbor island, which when zoomed out becomes, 4 pixels and then 2 pixels, so the seams don't just crack open.

I've always used 3, so I will try it with 16 now. Great advice.  

[Chic Aeon]

2 hours ago, AdamZadig said:

I've always used 3, so I will try it with 16 now. Great advice.  

If you look closely at the texture after it is baked you will see (or at least "I" see using my workflow and process)  that "padding" doesn't have the same quality of texture as that where the model is.  That extra padding was handy in the old days when we had a very bad problem of texture edges breaking up at a distance (sort of like bad LODs and it showed a sharp dark line where the seams met -- like on a vase) but that was fixed years ago.  

 

Of course it is good to experiment for yourself and test, but I use about 3 padding on a 2048 x 2048 texture and rarely have any dark areas. 

I work in Cycles Render now and bake all into one texture. So my method may not work for everyone of course :D.