Mayday said:
Hey, I'm interested in this whole LODding technique, could you elaborate on how to improve the method used in Oblivion?
Well, LoD stands for "Levels of Detail" and there just aint enough levels in Oblivion.
I'll be the first one to admit that Oblivion looks pretty good when you're standing right next to stuff, well except for people. :shock: The mountains in the far, far, distance also look OK. It does a piss-poor job of blending one into the other.
The first problem you notice is that the ground textures start to repeat obviously when they are more then a few feet away:
http://www.rpgcodex.com/images/news/View%205.JPG
Check out the grass just to the left of the cursor. See how it looks like a patchwork quilt? There are plenty of techniques to blend textures will smaller and smaller ones as they get farther away. Morrowind had, I think, six levels of this. The "quilt effect" was much less noticeable there. Also using better made textures can reduce this.
Also look at that same image just above the cursor. See how the grass goes from a high-res texture, to an ultra-low one? Just, BAM! Guar shit. Properly done this would be filtered to gradually fade from one to the next so the seam was a blend of the two textures. Also an interim level, or two, of medium detail textures would lessen the effect.
A third issue is the grid system. See how the high-res grass is applied to a square section of ground? A certain number of squares around the player are loaded with the high-res stuff, and the rest get the guar shit. It looks very unnatural. Properly done the engine would apply the high-res stuff in a circle around the player, and blend to lower-res ones as the radius from the player increases. Smoothly blended, not all looking like a checkerboard.
Then we have the LoD models:
http://www.rpgcodex.com/images/news/Disneyland%203.JPG
See how the houses look like little cubes? And they bear only a passing resemblance with the actual buildings inside Anvil? One can sub in a low polygon model as the player gets farther away. Only they've gone far too low a detail, far too soon. Notice also that the castle keep is visible, but the lighthouse right next to it is completely gone?
Only the major cites have any kind of LoD models. Notice how you can go waaay up into the mountains and still see the Imperial City? Yet, when you stand outside the Imperial City the hills look barren. They should be littered with forts, ruins, and towns. Imagine how cool that would look! They only bothered with the low-detail models for a couple of buildings. The engine could easily handle LoD models for most buildings, look how few polys are in that Anvil shot, like twelve per house! Plus a medium detail version in the middle would avoid the rinky-dink look when the player is only on a nearby hill.
It is easy to generate these low detail models in 3Ds Max, especially if you build the models with LoD in mind. Very little extra development time from the modelers.
Worst of all, IMO, is the "pop". As you move around all the things I mentioned "pop" into or out of view. All of them on this grid system too - so whole checkerboard squares, like an acre across, pop into view. Very disconcerting. Things should fade slowly into high detail, with more levels between high and low.
What I don't understand is how they managed to get SpeedTree to work as badly as the rest of their game? Try any of the demos, the one I played were released years before Oblivion. Lots more trees. They fade almost imperceptibly through six or eight levels of detail, with no annoying pop-in grids. Even the grass works better. How they managed to fuck up a turn-key tree solution is beyond me.
This did have somewhat of an effect on gameplay for me too. (just so I don't get flamed for being a graphics weenie) I found it very tedious and annoying exploring the hills around the Imperial City. You can clearly see the hills from the city, but the only detail you get is the rough idea of a road. Not until you go out there, fighting off something every two steps, do you get an idea of the lay of the land. Enormous forts simply pop up just before you stumble upon them. Then disappear before you reach the next town. Impossible to get a feel for what's where, and formulate a game plan. You really have to stumble around and take notes, or consult the map, when you could be seeing this stuff on-screen.
