Seam problem between two separate objects

[Nymoo]

Hello!  

Been working on an anthro head for a while, 90% of the time troubleshooting, the rest of the time actually progressing. At this point I need all the help I can get...

 

As far as I know, to simulate blinking (and jaw movements) from a mesh, there needs to be 'frames', of multiple heads. But that would be way too taxing, so separating the eyes from the rest of the head is a common thing to do.

 



But there's a problem, I don't know how to get rid of this ugly seam, it is an absolute deal-breaker, and anything I tried to find on google seemed like this is an innevitable outcome, at least regarding two separate objects breaking the seamless shading. BUT....


Here's a head from the talented Jig Itoku, his eyelid frames appear to be separate from the head, yet when they come together they are perfectly seamless in shading... Any ideas?

 

[Christhiana]

I think your problem is with the vertex normals on the edges of your object. I ran into this problem as well a while ago. There are solutions though! I'm not very good at making long posts that actually make sense so I'll link you to the thread I started about it. It contains some good information and solutions to your problem!

 

https://community.secondlife.com/t5/Mesh/Visible-seam-when-connecting-two-smooth-shaded-pieces/td-p/2921479

 

Good luck!

[Nymoo]

Thank you so much, identifying the problem after searching for a cause for 2 days feels like finding the holy grail... Avastar has fixed the problem for me, thank you <3 

[Drongle McMahon]

The thread that Christhiana refers to does contain a workaround for Blender (in case that's what you are using) that requires editing of the dae file. However, in the same thread Gaia mentioned the forthcoming introduction of custom normal editing to Blender. This is now available* and produces a much more effective way of producing the same effect. The technique in Blender, using the Data Transfer modifier, is quite complicated, but when learned allows accurate matching of the normals at the edges of different objects (as well as other useful things). I think Avastar has a much more accessible interface to do this (and could do it even before it was introduced into Blender). So if you are using Avastar, it should be easier. If you aren't using Blender, then I believe other advanced programs have at least equally effective methods for editing the normals.

*eg here and here.

[Nymoo]

Thanks, I am using Blender yes, and it appears that there's yet another problem. Guess I'm not let off that easy!

 



The object on the right was the one I uploaded first, with desirable results, however the one on the left is 

the second upload, the seam appears on the head side of things this time. The difference between the two is that the 

eyelids(5 of them) from the first head (one on the right) are all joined together, so the head and the eyelids are 2 objects.

The one on the left are 6 objects, the head and 5 eyelid frames. The reason why I want both uploaded is to find a script

and test out which one would work for blinking, since I have literally 0 experience of it and I know both joined and

individual eyelids are possible.

In any case, it appears that having 5 objects overlapping over each other creates a light shading seam on the head itself

this time. 


as shown here. It's not ambient occlusion either, I checked. It's not catastrophic by any means, but since I plan

to market this thing it might as well be as good as it can get.

I'll check out your links, perhaps I can tweak the problem trough Data Transfer, I just wanted to mention it here just

in case you or anyone else had an easy answer to this. Thank you again!

 

[Nymoo]

Just wanted to mention, with a bit of tweaking (and realizing vertex groups are my friend) I had success... FOR NOW.

 

Thanks a lot for your help! That guide in the other thread helped a lot.  I don't care how complicated something is as long as it works lol.

[Christhiana]

Glad to hear it all worked out! Besides me not being very good in explaining things I thought the other thread would be a good read. It contains so much more information besides the solution to the problem.

 

I know that "Holy Grail" feeling.... when I got the vertex normals doing what I wanted them to do I ran through the house dancing and jumping!