[opensource-dev] Interested in Terrain Advancement
Dzonatas Sol
dzonatas at gmail.com
Fri Apr 23 13:26:10 PDT 2010
There does seem to be a collective feel that the terrain needs to
upgraded somehow. Even a Linden suggested maybe a way to override it if
the builder choses, like with sim sized mega prims.
My first concern is LOD. The constant changes of LOD on the terrain make
the appearance the terrain unnatural and unstable. There are times where
we spend lots of time to get the terrain to look just perfectly aligned
with other objects nearby. When one decides to walk away 20m, 40m, 60m,
however, the perfect alignment becomes a prefect fashion statement for a
drunk bulldozer. The hard work undertaken to detail the alignment of the
terrain seems like a complete loss.
As I've used other renders, lets pick on Call of Duty, the terrain is
pretty stable even at a distance. It has to be. The mere jump of LOD in
the terrain could mean a way to cheat in Deathmatch sniper rounds. You
know how snipers love to crawl around the terrain. That kind of
stableness doesn't happen when the drunk bulldozer decides to
rearrangement the landscape every frame you move. Call of Duty uses the
Source Engine, yet this isn't a 'lets all switch over to the Source
Engine' rant. It is a use-case that shows that even on old steampunk
video cards there still have the coal to burn up the pixels and display
a stable landscape. The use-case means, bottomline, it is possible.
Maybe a baby-step solution is just to have an option to turn-off the LOD
for the current sim, and maybe nearby sims. The problem here, maybe, is
that the changes to add vertex limits would be affected by this. It
might not be all that simple like it was in the past without the vertex
limits. Therefore, there would need to be separate vertex limits: one
for the terrain and the rest for objects.
Here is another use-case with a collada file: Lets say I have a collada
file that contains a very detailed structure of a volcano (terrain
only). The volcano is 1km wide. That crosses several 256m sims. There
are lava tunnels that lead inside.
The suggested solution was to use a sim sized mega-prim. To do that with
scuplties would be hard for more than just looks. Sculpties need to
calculate all the phsyics, yet the collada file could have that already
detailed and compiled with the file.
How do we do this with the stock viewer even if we used sculpties? The
stock viewer doesn't include a "sit on this object here like one sits on
land now anywhere" option. If we used a mega-prim, it would disabled the
ability to sit anywhere on the terrain.
The other idea is to import a terrain, which is an available feature.
That doesn't allow us to have multiple height maps, like lava tubes. If
a lava tube crossed a sim to another, there would be a hole in the
terrain in one sim. There current terrain engine doesn't allow holes.
Multiple height maps would allow us to have holes in the terrain. The
physics detail of a scupltie bent to make that hole doesn't preform (and
I don't mean just frame optimization.. I mean like how a skirt clearly
either looks good or not when you sit down kind of 'preform'.)
So, maybe the solution include that baby step.. to allow multiple height
map layers. A Lava tube could be done with three layers. One for the
bottom of the tunnel. One for the top. And one for the side of the
volcano above the tunnel. There would be needed an extra feature with
the height map to allow empty spaces, to allow where the tunnel opens
into the side of the volcano.
So, before we even digress into the advantages of collada refineries, it
seems the first two baby steps would be to fix LOD and allow an
arbitrary number of terrain layers.
I would like to see what others think about this.
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