Archived

This topic is now archived and is closed to further replies.

feisar

Unreal 3 Engine

Recommended Posts

feisar    122
Anyone knows what exact system Unreal 3 Engine will use in order to achieve their "full support for seamlessly interconnected indoor and outdoor environments with dynamic per-pixel lighting and shadowing supported everywhere"? Octree/Portal Hybrid? Any clues?

Share this post


Link to post
Share on other sites
haro    502
quote:
Original post by MikeMJH
At any rate, they''re probably going to be using some occlusion culling, in my opinion.


Wow!!! Do you think they might do view frustum culling too????

Share this post


Link to post
Share on other sites
SnprBoB86    277
skip the sarcasim...

current versions of the unreal engine use no "occlusion" culling as far as I know.

The engine relies primarily on portals which do cull occluded objects, but culls them on the assumption rather than actually checked to see if it is occluded. The assumption is that if the portal is outside the frustum or occluded, and the portal is the only way 2 see into a sector, than the sector must be occluded.

MikeMJH was most likely refering to view space occlusion culling methods such as HOM which is similar to gfx cards heirarchical Z buffers.

Share this post


Link to post
Share on other sites
feisar    122
Well unrealtechnology.com refers to 'seamless' integration of outdoor and indoor scenes. Portal Rendering, as far as I understand it, does indeed cull unseen objects (depending on how you define 'occlusion culling').

Get Room->Get Portals->Get New Rooms->Clip New Room Geometry based on the Portals-> etc.

In my oppinion, a Portal Engine is a bit outdated and I can hardly imagine the Unreal 3 Engine (and even current versions of the engine) to purely rely on a non-hybrid approach.

[edited by - feisar on May 26, 2004 1:21:50 AM]

Share this post


Link to post
Share on other sites
Cypher19    768
According to one of my friends who''s tooled around in the Unreal3 editor, projectors (judging by the use, I''d say they''re Unreal''s form of portals) are used for even outdoor environments. Doesn''t the Unreal 2 engine already support seamless indoor/outdoor environments anyways?

Share this post


Link to post
Share on other sites
Fidelio66    164
quote:
Original post by SnprBoB86
skip the sarcasim...

current versions of the unreal engine use no "occlusion" culling as far as I know.



It also has antiportals, which serve as occluders. This was in UT2003, don''t know if it was already in the original UT. Antiportals are usually hidden inside hills and walls and allows the engine to skip rendering objects if their bounding box is behind them completely.

Share this post


Link to post
Share on other sites
haro    502
quote:
Original post by feisar
Well unrealtechnology.com refers to ''seamless'' integration of outdoor and indoor scenes. Portal Rendering, as far as I understand it, does indeed cull unseen objects (depending on how you define ''occlusion culling'').

In my oppinion, a Portal Engine is a bit outdated and I can hardly imagine the Unreal 3 Engine (and even current versions of the engine) to purely rely on a non-hybrid approach.



Portal systems are preprocessed ( or human defined ) occlusion culling systems. Outside of hierarchical based view frustum culling, portals often give the next best way to eliminate alot of geometry with little effort.

I did not mean to come off as antagonistic as I did with my reply. However, any modern engine will make extensive use of various occluding methods. Another typical method is to keep a list of current visible large occluding regions/objects and then to do occlusion tests against those ''masks''/occluders each frame. As the view changed, the occluder list would be tweaked obviously.

Share this post


Link to post
Share on other sites
mhamlin    520
quote:
Original post by SnprBoB86
MikeMJH was most likely refering to view space occlusion culling methods such as HOM which is similar to gfx cards heirarchical Z buffers.


Yes, this is what I meant. I should''ve been more specific. Anyhow, thanks for the defense, SnprBoB86.

Share this post


Link to post
Share on other sites
Extrarius    1412
the Unreal engine 2 suppports seamless integration if by that you mean "you can have terrain and walls". If you meant instead "you can have indoor and outdoor areas with equal(good) speed without too much difficulty" then no, it does not support them like that. The engine supports heightmaps and CSG primatives (cube, pyramid, cylinder, geosphere), but to get any real speed in 'outdoor' areas is very tricky. The engine only does any kind of automatic culling on completely seperated subtractive brushes. To get speed, you must manually place portals(even in 'outdoor' areas) and 'antiportals'(brushes that occlude what is behind them). Getting fast outdoor areas is a nightmare because you essentially have to make it like indoor areas with very limited view distances through creative use of hills, trees, random debris laying around etc (and then put antiports around such things so they actually occlude in the rendering pipeline).

The engine doesn't really support wide, open outdoor areas like the serious engine did. Well, maybe if you have the 9800 pro or equiv it would run at ok speeds, but to get it to run on old cards (like the default maps in ut2004 runs on my 8500 at 50+ fps with good detail) you essentially have to treat outdoor areas like indoor areas with curves instead of steps.

[edited by - Extrarius on May 27, 2004 8:01:02 AM]

Share this post


Link to post
Share on other sites