Huge world - Tiled but seams on borders

Bug Reports
#1

Hi guys,

First, i would like to apologize if my english isn’t correct.

So, the problem i encounter is that some seams appear on each edge of my tiled world. I don’t know if i have to change options in worldmachine to don’t have these seams. I played with “the blending percentage” and the “share edge vertices” but it only change the vertice elevation and vertice consistency between each part. Here, vertices are really snaped but seams are there anyway. So i precise the seams aren’t on the diffuse but it only appear in Unity or other 3d software.

What does it mean ? How can i fix it ?

On the attached picture, i isolated a border between only two tiled parts. But in my scene, i got 16 tiled pieces .

Thanks

#2

Hi there,

Usually for seams the big culprit is having edge vertices matching on – blending will improve tile to tile coherency but will do nothing about a 1 pixel seam.

If you’d like, you can send your world to support@world-machine.com and I will take a look at it. I have heard a few reports from people of seams in their output, but usually it shakes out to the #1 reason mentioned above. If there might be a bug inducing seams I would definitely like to know!

Regards,

#3

Hi there,

I’ve taken a look at the files you sent me. Here’s what I’ve found out:

The problem is very probably not with the World Machine output. I performed a tiled build and then re-imported the tileset using the Tiled File Input to inspect the terrain; no seams were evident. I also manually imported and compared several tiles as a double check which likewise passed. There was a slight “lumpiness” to the tile transitions in a couple places that turning the blending percentage to 50% improved.

I then tried doing some Unity terrain imports and lining up the terrains next to each other in Unity, where you can indeed show a seam. Crucially though, I believe there are a couple points here that might be contributing, and that can be fixed:

[ol][li]I’m not entirely certain the Unity is playing well with a 512x512 sized heightfield input; try setting the tile resolution to 513x513 (or whatever size terrains you are using in unity). This may not matter however, compared to… [/li]
[li]The default lighting is incorrect across the two terrains even though their vertices line up perfectly, because Unity has no way of properly blending the normals across the shared vertices.[/li][/ol]

You can solve the latter problem by baking your lightmaps in World Machine and importing them. There’s probably a better way (I will admit to limited knowledge about working in Unity!) but the following image shows the seam when using Unity’s built in lighting or built in lightmap baking, and then the same thing with lightmaps exported by world machine and used to replace the built-in lightmaps:

built-in is on the top, WM lightmap is on the bottom. I obviously didn’t attempt to actually match the scene lighting, but you can see the difference.

Perhaps someone else here who is experienced with Unity could help you further – there must be some standard ways to do tiled terrains within Unity that attempt to solve the lighting problem.

update: I did some quick googling and apparently you can inform Unity which terrains border each other at runtime so that it uses current LODs across boundaries, etc, which will certainly help…

#4