22 réponses à ce sujet

[rjshae]

The larger models in NWN2 (such as buildings) include an L01/L02 packet version of the model, presumably for longer range rendering. Does anybody have some useful heuristics on how much I should trim the meshes for those parts? Or is that even an issue any more with current cards?

[Tchos]

Some useful info here:

http://forum.bioware...-limits-repost/

[rjshae]

Buildings: 1600 faces per tile - The polygon count gets categorized a little differently for buildings. Most buildings tend to be large and span multiple tiles. They are allowed to have a higher polygon count, because usually, the player only sees a small part of the building at a time. For example, a building that fills up 8 tiles could get away with a polygon count of 12,800 or less, while a building that only filled 2 tiles would need to be kept smaller than 3200 faces. Still, I don't recommend making any building with more than 20k polys, regardless of its tile footprint

 

Okay, that gives a recommendation for total polygon count. But I'm not sure how to interpret that in terms of the L01/L02 face count requirements. Maybe I use half the polygons at double the distance? Anyway, I don't even know how far away the player needs to be before the L01/L02 kicks in.

 

I guess I can just look at a few existing models and try to get an idea.

 

Another thing I'm wondering now is, do the BCK placeables use L01/L02? If not, does that get very expensive in terms of rendering? Maybe I don't need to worry about it.

[Tchos]

I can't say for sure, or give details on the other questions, but I believe that the lack of LOD models in the City Hak placeables is causing the performance to suffer greatly.

[rjshae]

I checked a couple of house models:

 

PLC_BR_HOUSE1:

• Main => 1,493 faces
• L01 => 1,017 faces
• L02 => 748 faces

PLC_BR_HOUSE2:

• Main => 1,325 faces
• L01 => 985 faces
• L02 => 678 faces

so roughly a ratio of 100:75:50%.

[rjshae]

I ran an experiment with a model that has three parts: the main model, an L01 version rotated 45 degrees, and an L02 version rotated 90 degrees. (Shown overlapped in the upper left.) Next I placed copies of the model a half grid square (5m) apart, extending off into the distance. Here is the result:

 

 

It's interesting that the toolset switches to the L01 version just a grid square away, then the L02 version after one and a half grid squares. Oddly, even further away, it seems to switch back to the original model again.

[Eguintir Eligard]

I figure two thirds then one third. Consider this mandatory for modelling, as are mip maps.

City hak or other major placeables in the cornucopia that don't have lods would make an even better project t than reskins and tint maps. I'll either delete or add lod s to any content I use. Full rendering at distance is unacceptable... Thats not how things work in real time

[4760]

so roughly a ratio of 100:75:50%.

For the wraith spider: 1464 --> 940 --> 584 (100%, 64%, 40%)

For the mindflayer: 2162 --> 1460 --> 596 (100%, 67%, 27%)

 

I try to keep L01 at 60% and L02 at 40% of the full model.

[rjshae]

I wonder, does anybody know if the L01/L02 additions work with tilesets as well?

[Mer1]

It's interesting that the toolset switches to the L01 version just a grid square away, then the L02 version after one and a half grid squares. Oddly, even further away, it seems to switch back to the original model again.

 

I checked few stock placeables in game and toolset and in both cases the distance is bigger.

Based on the far clip in night/day fog settings the distance before the L01 switch occurs is around "90".

[rjshae]

I checked few stock placeables in game and toolset and in both cases the distance is bigger.

Based on the far clip in night/day fog settings the distance before the L01 switch occurs is around "90".

 

Hmm... perhaps it depends on the placeable then? Number of polys vs. distance? Or it could vary based on graphics settings.

[Loki_999]

 

It's interesting that the toolset switches to the L01 version just a grid square away, then the L02 version after one and a half grid squares. Oddly, even further away, it seems to switch back to the original model again.

 

Perhaps this means its looking for a L03 version, and not finding it, reverts to default.

[Mer1]

Hmm... perhaps it depends on the placeable then? Number of polys vs. distance? Or it could vary based on graphics settings.

 

Graphic settings make no difference, don't think the rest makes either. The placeables I checked - samarach house 4, thay wall, rural lighthouse. Here is shown the max distance, at which they still use the base model.

 

 

Switch to L01 is at distance of 90, to L02 at 180.

[rjshae]

Well there must be an explanation for why our results differ so markedly.

[Mer1]

Can you upload that model you made or just check if the stock placeables show the same behaviour on your system? That Samarach house 04 is easy to check because that upper wooden part of the model on the top of the roof changes visibly between the lod transitions.

[rjshae]

Sure, I'll give it a try tonight. Mine was tested in a 32x32 area and I notice yours is much smaller.

 

Perhaps this means its looking for a L03 version, and not finding it, reverts to default.

 

I'll bet you're right. But the default behavior probably should have been to use L02.

[Loki_999]

I'll bet you're right. But the default behavior probably should have been to use L02.

 

*drum roll* Bugsidian strikes again!

 

Could also explain why some large areas with lots of placeables suffer more of a performance hit than they should when rendering distant objects.

 

You can make a L03 version and test?

[-Semper-]

there's no third lod. i also never experienced that the lvl2 lod will be replaced by lvl1 farther away, never explicitly tested it though.

[Eguintir Eligard]

Yes I'm surprised this isn't common knowledge. There are several Nwn2 tutorials and obsidian articles that tell you why there are lod models and that there's only two. Speculating will only confuse new modellers.

[rjshae]

Graphic settings make no difference, don't think the rest makes either. The placeables I checked - samarach house 4, thay wall, rural lighthouse. Here is shown the max distance, at which they still use the base model.

 

 

Switch to L01 is at distance of 90, to L02 at 180.

 

I did some experimentation with the block model: the distance at which L01 kicks in is dependent on the size of the model. When I increased the dimensions by 300%, L01 happened about three times further out. This seems to makes sense from the perspective of larger models having a larger subtended angle across the display. (It also suggests that adding an L01/L02 on smaller static models may be a wasted effort, since you'll mostly see them in the L02 mode. Might as well just make it a low poly model.)

 

Changing the number of faces on the model didn't have any impact.

[Eguintir Eligard]

I think you might find that basic objects (such as barrels, chests, the small simple stuff) is already L02 as you alluded to... as in, there are no ways to further reduce face count without compromising the entire structure, as it would cease to be what it is supposed to be.

 

In that sense, yes extra models would be wasted but you would probably find them impossible anyway.

 

On this note, since it hasn't come up yet in the fatty project, I am curious what happens to the texture mapping seams when you delete edges to reduce polygons for these models. I am assuming nothing as long as you don't delete the edges that the seams are on, and keep the same overall shape, rougher though it may be. Confirm / deny?

[Mer1]

I did some experimentation with the block model: the distance at which L01 kicks in is dependent on the size of the model. When I increased the dimensions by 300%, L01 happened about three times further out. This seems to makes sense from the perspective of larger models having a larger subtended angle across the display. (It also suggests that adding an L01/L02 on smaller static models may be a wasted effort, since you'll mostly see them in the L02 mode. Might as well just make it a low poly model.)

 

Changing the number of faces on the model didn't have any impact.

 

Cool, so it's the size that matters. Nice findings.

[-Semper-]

On this note, since it hasn't come up yet in the fatty project, I am curious what happens to the texture mapping seams when you delete edges to reduce polygons for these models. I am assuming nothing as long as you don't delete the edges that the seams are on, and keep the same overall shape, rougher though it may be. Confirm / deny?

 

yes, try to avoid to delete edges marked as uv seams. else you have to unwrap your model again.