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dynamic LOD - PowerRender

Started by McMcDonald 5 replies 750+ views
Original Post
McMcDonald
McMcDonald
Hi! I am looking at game engines and at the PowerRender FAQ section there is the following comment: H.2 - Does the engine use dynamic LOD on the terrain? No. The engine is optimized for the latest 3D cards with hardware transformation and lighting. This means it is faster to keep the terrain vertices on the card rather than changing them every frame for LOD calculations. This means the terrain will not change shape as you move around (as in Black and White for example). What do you think: is it really good to do terrain visualization without some LOD-algorithm ? Or is this only possible with a few high end video cards ? Thanks McMc
elis-cool
elis-cool
Or you could just use GeoMipmapping
[email=esheppard@gmail.com]esheppard@gmail.com[/email]
McMcDonald
McMcDonald
Hi!

Thanks, a very interesting article.

==> If i want to make outdoor games (flight sims, racing sims,...) the power render will not be the first choice.

Fidelio_
Fidelio_
quote:
Original post by McMcDonald

H.2 - Does the engine use dynamic LOD on the terrain?

No. The engine is optimized for the latest 3D cards with hardware transformation and lighting. This means it is faster to keep the terrain vertices on the card rather than changing them every frame for LOD calculations. This means the terrain will not change shape as you move around (as in Black and White for example).


What do you think: is it really good to do terrain visualization without some LOD-algorithm ? Or is this only possible with a few high end video cards ?


For smaller patches, maybe. A vertex is typically 3x4 bytes for coordinates, 3x4 for normals, 2x4 for texture, that''s 32 bytes.

128*128 is 16384, that would be 32768 triangles, ok. that''s 1 MB of memory.
256*256 takes 4 MB on the card. 512*512 takes 16 MB. 1024*1024 takes 64 MB, for 2 million triangles.

It could work, for 128x128 or 256x256, on faster cards. but a LOD algorithm like Rottgers or Diamond would still be faster on slower cards.

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