hard seams in one object
by Ivan Mandzhukov · in pureLIGHT · 09/13/2009 (5:45 am) · 6 replies
I am having a problem with hard seams. They appear in one object where different polygons of it have different Material IDs. I use for the whole object one Multi-Sub object material. Is there a way that can be fixed? If I assign just one material for all the polygons in the mesh the hard seams disappear. But I need several textures for the mesh at all... the model is VL_object.
#2
my model i complex. It is a whole level with walls , grass plane and buildings. The hard seams appear between faces with different material IDs. The model is smoothed , i can see that in 3ds max , there is no problem to have different material IDs for its faces but in PureLight that obviously matters.
I don't think adding more vertices will solve the problem. Anyway doing this could lead to potential problems after that because I intend to use the visible mesh for collisions.
I've found a way to solve the hard seams problem to some extent. But not entirely. In short: I use one huge texture for the whole object and all the scene textures are parts of this huge diffuse texture. But now i have problems with tiling the ground texture of the model. The only possible way is to tile it to the X axis of the map. But this leads to another technical problems with unwrapping and I don't think this method of unwrapping will be successful because it needs a lot of work to do with unwrapping and sometimes if I have to change something little in the level this could lead to serious problems. I wish PureLight could handle different material IDs in the way that 3ds max handles it...
Anyway I would be happy to hear any ideas that could lead to success. :)
09/14/2009 (8:33 am)
thanks for the support, Andrew,my model i complex. It is a whole level with walls , grass plane and buildings. The hard seams appear between faces with different material IDs. The model is smoothed , i can see that in 3ds max , there is no problem to have different material IDs for its faces but in PureLight that obviously matters.
I don't think adding more vertices will solve the problem. Anyway doing this could lead to potential problems after that because I intend to use the visible mesh for collisions.
I've found a way to solve the hard seams problem to some extent. But not entirely. In short: I use one huge texture for the whole object and all the scene textures are parts of this huge diffuse texture. But now i have problems with tiling the ground texture of the model. The only possible way is to tile it to the X axis of the map. But this leads to another technical problems with unwrapping and I don't think this method of unwrapping will be successful because it needs a lot of work to do with unwrapping and sometimes if I have to change something little in the level this could lead to serious problems. I wish PureLight could handle different material IDs in the way that 3ds max handles it...
Anyway I would be happy to hear any ideas that could lead to success. :)
#3
It seems to me (now I'm not an artist by any means), but, keeping everything in one giant model is going to be causing extra work and complications when you do have to go and make a change to it later on.
09/14/2009 (12:48 pm)
Can we have a screenshot showing the seams?It seems to me (now I'm not an artist by any means), but, keeping everything in one giant model is going to be causing extra work and complications when you do have to go and make a change to it later on.
#4
Let me explain. This is one object that has different material IDs for some sets of faces. This is done via MultiSub object material in 3ds max.
All the vertexes between two sets of faces with different material IDs are welded . All the faces are smoothed via 1 smoothing group. In 3ds max they appear all smooth, but after baked in pureLight these seams appear.
09/14/2009 (1:02 pm)
Let me explain. This is one object that has different material IDs for some sets of faces. This is done via MultiSub object material in 3ds max.
All the vertexes between two sets of faces with different material IDs are welded . All the faces are smoothed via 1 smoothing group. In 3ds max they appear all smooth, but after baked in pureLight these seams appear.
#5
The grass material looks the same between ID1, 2, and 3 - with a different material on the walls - would you be able to have those grass sections on a single material ID? (and not necessarily the walls or such?).
More geometry by the seam might make a big difference, but I would strongly recommend even an extremely low resolution lightmap. You might still have a potential seam, (though it should be _far_ less pronounced with even a few texels across that distance instead of a single vertex blend). A lightmap is also easier to handle - you can make manual adjustments
I wish we had a better answer, but the way blending works requires a single material ID. I know that max will show smoothing, but unfortunately we cannot blend across boundaries like such at this time. We will consider adding support for this to future builds though.
I hope this helps,
A
09/14/2009 (5:20 pm)
That is a fairly worst-case situation - vertex lighting breaks down on extremely low poly geometry, and the material ID seams are right on what look like major changes in angle.The grass material looks the same between ID1, 2, and 3 - with a different material on the walls - would you be able to have those grass sections on a single material ID? (and not necessarily the walls or such?).
More geometry by the seam might make a big difference, but I would strongly recommend even an extremely low resolution lightmap. You might still have a potential seam, (though it should be _far_ less pronounced with even a few texels across that distance instead of a single vertex blend). A lightmap is also easier to handle - you can make manual adjustments
I wish we had a better answer, but the way blending works requires a single material ID. I know that max will show smoothing, but unfortunately we cannot blend across boundaries like such at this time. We will consider adding support for this to future builds though.
I hope this helps,
A
#6
I have tested the above model split up into three LMA objects and the results are better. But there is an obvious difference between LM and VL objects. Sometimes VL objects look better (exteriors for instance).
Anyway thanks a lot. I will decide myself what setup would fit best for my scene.
09/14/2009 (5:55 pm)
Actually I've already tested that if everything use one material(one texture) those problems disappear. I am talking about VL object.I have tested the above model split up into three LMA objects and the results are better. But there is an obvious difference between LM and VL objects. Sometimes VL objects look better (exteriors for instance).
Anyway thanks a lot. I will decide myself what setup would fit best for my scene.
Andrew Czarnietzki
Can you give me some more information on your specific model? Would it be possible to have the material transition on a hard edge or in a less noticeable location? Would you be able to insert some more vertices near the seam - the large problem with vertex lit objects is that a lighting result can get stretched for comparatively extreme distances, and inserting some interim pieces can often soften this a little.
I hope this helps!
A