Normal Map Mirroring & Overlapping woes in UDK....SOLVED!?
polycounter lvl 9
I'm posting this because I know there are many people out there who have no idea how to fix this problem, or have been searching tirelessly like I was recently. As far as I know and as far as I've seen and read, I have not seen anyone actually come up with a clear solution for this problem.
What's the problem when using overlapping UV's for your normal map and modular pieces in UDK?
As you can see, the shading is obviously very different. For this model in particular, one quarter of it was modeled only. The UV's were then laid out, and then that quarter piece was duplicated 3 times and placed appropriately to make the rest of the bridge. The texture is not square either, so that adds to the complexity of the issue. The texture is 2048 x 1024. This is important to remember for reasons later on.
So, how do we fix this issue with what we have going on here?
For people using square textures, and people using rectangular 2:1 ratio textures, there is only 1 difference. That difference is where you place your overlapping UV's!
See here, for this particular model, I moved my UV's over by every other tile, using UV Deluxe (get it,makes things easier)...
But as stated in the image, I would assume someone using a 1:1 square texture would only have to move it over left or right by 1 tile.
I will also assume here, that it does not matter whether you place your extra overlapped UV's to the right, or to the left. As long as they are in the Positive (+) V space. Meaning, anywhere U direction. I could possibly be wrong about this point, though.
Anyways, once you've placed your UV's appropriately and re-export as FBX, UDK is happy!...
I also want to make note, that if you are still getting that shading problem, turn OFF your "Tangents and Binormals" option whilst exporting as an FBX!
I really hope this helps people, because for some reason I was not able to find a source to clear this issue up. When I finally figured this out, I wanted to scream with joy lol...
What's the problem when using overlapping UV's for your normal map and modular pieces in UDK?
As you can see, the shading is obviously very different. For this model in particular, one quarter of it was modeled only. The UV's were then laid out, and then that quarter piece was duplicated 3 times and placed appropriately to make the rest of the bridge. The texture is not square either, so that adds to the complexity of the issue. The texture is 2048 x 1024. This is important to remember for reasons later on.
So, how do we fix this issue with what we have going on here?
For people using square textures, and people using rectangular 2:1 ratio textures, there is only 1 difference. That difference is where you place your overlapping UV's!
See here, for this particular model, I moved my UV's over by every other tile, using UV Deluxe (get it,makes things easier)...
But as stated in the image, I would assume someone using a 1:1 square texture would only have to move it over left or right by 1 tile.
I will also assume here, that it does not matter whether you place your extra overlapped UV's to the right, or to the left. As long as they are in the Positive (+) V space. Meaning, anywhere U direction. I could possibly be wrong about this point, though.
Anyways, once you've placed your UV's appropriately and re-export as FBX, UDK is happy!...
I also want to make note, that if you are still getting that shading problem, turn OFF your "Tangents and Binormals" option whilst exporting as an FBX!
I really hope this helps people, because for some reason I was not able to find a source to clear this issue up. When I finally figured this out, I wanted to scream with joy lol...
Replies
Even if mentioned in the FBX documentation, the triangulation has no effect (whatever method I use to do it).
(Tested with FBX 2013.2 (using exporter set on 2011 file version) and UDK January 2012.)
There is another point that I failed to mention in my previous post, and it is that when you import your normal map texture into UDK, you should set the "Address X" mode to "Mirror", and make sure your "Unpack Min" settings for (0), (1), and (2) are "-1." This is actually very important and I don't know how I missed it lol! Let me know if that changes anything for you Froyok!
I will give a try to the last version of the UDK, since it load correctly the Tangent/Binormals (related to the xNormal workflow).
[EDIT] I just tested with a skeletal mesh : when the Binormals are disabled the mirror works fine.