Levels of Detail (LOD)

[pepperman]

I know model levels of detail (LOD) have been discussed before but just to make sure I am straight I'd like a confirmation on the following summary.

1. Armada uses up to four levels of detail (Lod0, Lod1, Lod2, and Lod3).

2. Lod0 is the zoomed out look (100 to ~ 75 percent zoomed out

3. Lod1 is the second zoom level ranging ~ 75 - 60 percent zoomed out

4. Lod2 gets closer ranging from about ~ 60 to 50 percent zoomed out and

5. Lod3 is the level where the details are displayed in all their glory (less than 50 percent zoomed out)


Does this track with everyone experience/undestanding?

 

[MrVulcan]

I think that's about right. I'm not sure about which is highest/lower, at least at the internal names in the hierarchy. The Lods might be chosen automatically regardless of the number you append to "Lod" in the hierarchy.

The exact distances for Lod transitions are in ART_CFG.h

// Levels of detail based on depth
float DETAIL_4_LOD_0_DISTANCE = 650;
float DETAIL_4_LOD_1_DISTANCE = 250;
float DETAIL_4_LOD_2_DISTANCE = 100;

So:
(inf-650) - Lod0
(650-250) - Lod1
(250-100) - Lod2
(100-0) - Lod3
Whether or not these are used, I'm not sure. 100 units is very close for the best Lod. It feels as if the transition happens further away ingame.

Edit: The max zoom out is about 700 units in stock armada.. I think.

 

[pepperman]

I figured it was defined someplace. I tried a quick test in A2 with four lods and they all transitioned accordingly. From A1 and A2's ART_CFG.h file, I see there are in fact various configurations based on what type of machine (speed wise) you are running: Configuration 0,1,2,3 and 4. Lods 0,1,2, and 3 are defined for A2; whereas only Lods 0,1 and 2 are defined for A1. Learned something new today. Thanks Mr. Vulan for the education.

From A2's ART_CFG.h file:

// Levels of detail based on depth [[Configuration 0]]
float DETAIL_0_LOD_0_DISTANCE = 300.0;
float DETAIL_0_LOD_1_DISTANCE = 100.0;
float DETAIL_0_LOD_2_DISTANCE = 50.0;
float DETAIL_0_LOD_3_DISTANCE = 25.0;

// Levels of detail based on depth [[Configuration 1]]
float DETAIL_1_LOD_0_DISTANCE = 450.0;
float DETAIL_1_LOD_1_DISTANCE = 150.0;
float DETAIL_1_LOD_2_DISTANCE = 75.0;
float DETAIL_1_LOD_3_DISTANCE = 35.0;

// Levels of detail based on depth [[Configuration 2]]
float DETAIL_2_LOD_0_DISTANCE = 500.0;
float DETAIL_2_LOD_1_DISTANCE = 200.0;
float DETAIL_2_LOD_2_DISTANCE = 100.0;
float DETAIL_2_LOD_3_DISTANCE = 50.0;

// Levels of detail based on depth [[Configuration 3]]
float DETAIL_3_LOD_0_DISTANCE = 600.0;
float DETAIL_3_LOD_1_DISTANCE = 240.0;
float DETAIL_3_LOD_2_DISTANCE = 120.0;
float DETAIL_3_LOD_3_DISTANCE = 60.0;

// Levels of detail based on depth [[Configuration 4]]
float DETAIL_4_LOD_0_DISTANCE = 700.0;
float DETAIL_4_LOD_1_DISTANCE = 300.0;
float DETAIL_4_LOD_2_DISTANCE = 150.0;
float DETAIL_4_LOD_3_DISTANCE = 75.0;

 

[Starfox1701]

Actually A2 will support up to 5 LODs as I implemented in this file

http://www.msfc.com.au/forum/downloads.php?do=file&id=610

It should also be noted that texture LODs can be used without the corresponding Mesh LODs. The program handles this automatically and doesn't require any additional rigging of the model or special export. Of the 2 Textures are by far the greater drain on system resources but there is an upper to the max polies that the engine can render. I want to say for stock it is around 100k for an individual mesh and about one million overall. Limiting the number of meshes is also important. I don't know if the max version has a limit but milkshape could only do about 30 and an model running more then 4 or 5 at a time will tend to cause lag. Properly LODes I have run models up to 25K with 2048X2048 textures on an older marginal system without real problems. pics for evidence

https://www.dropbox.com/sh/82axsv20iqnrc9p/6p7LXhY-0U

 

[Chiletrek]

Hello:
That is very interesting, really, but even if this helps a lot to have a great game experience, I would still try to use the less number of polygons as I can (but keeping a good-looking design) and to try to have just 1 texture file per entire model, as texturesd could usually be resized. I guess that , combined with LODs and we could get BC-style games .