strange bug with models....

[Indy 0]

Hi, i've noticed a strange bug happening to one of my models.

I've imported it from 3d studio and in O2 the face count is around 6800. If i recalculate the normals, and add the smooth edge tool (I) on all faces, nothing happens in game and it's working but if i use on all faces the sharp edges tool it will screw up the model as you can see in the screenshots (after some seconds the game crashes). I still have to work on the normals and add smoothing where needed but i don't know if it will be working.

I don't think it's a model bug because iv'e tryied to place some original T80's in the same lod to reach my same polycount and i had the same bug.

If it can be helpfull i have a Radeon 9000 pro 128 DDR, with Catalyst 4.7 and this bug happens (at me) only on this last driver set, as you can see a test with older drivers http://ofp.gamezone.cz/_hosted/ophusky/images/ab41_ingame.jpg

[Indy 0]

I've done some more test, i've tryed on other video cards and with other drivers and i found that the bug is caused by the "HW T&L" Acceleration. If i disable it in the configuration window the model works without any bug, but when i activate it i have the problem with the model.

It's not related with drivers or video card, i have tryed with different drivers (cat 4.3, 4.4 and 4.7) and different video cards (radeon 9000, radeon 9800, radeon 8500 and on a Ge Force 3 with lastest drivers installed) and the problem happens only when the HW T&L is active.

[philcommando 0]

wish i could help...but i am a lousy 3dman..hardly tamper with the smooth or sharp edges!!!! Sure would like to learn from u on how u can solve the problem but i do know that smoothing generally creates more faces to make it more rounded - more faces = more vertices for engine to process - scary thot there if using together with kegety's inbuilt ofp's only mirror!!!!.

[Indy 0]

no because you work on normals, and not on faces, if you try to smooth a cilinder in O2 you just select faces that must look smooth and press I. This will change the lighting on the model but not your polycount. Also without the HW T&L acceleration it works fine, the problem happens only when HW T&L is active.

And the version of the model that is smoothed works in game with HW T&L without bugs, the problem is on the sharpen one.

And it's a WW2 car, a lot of faces must look sharp.

I think it's an engine bug... the only way i know to fix this is deleting some details and lower the number of sharp faces or it will be not working with users that use HW T&L (like me ). I hope on a BIS explanation about it.

[Crowley 0]

6800 is a little on the high side to start with.

[Indy 0]

i don't think 6800 is high, maybe is higher than what is supposed to be low poly, but the limit is something around 30.000 faces and 6800 is a lot below of this limit. And current video cards can support it without lag, i run them on an ati 9000, nothing special, and i don't have a noticeable loss of fps

[suma 8]

My guess is that what you are seeing is overflowing vertex count limit, which is something like 32767 (each vertex needs to be represented by signed 16-b index). Vertex is each combination of point/normal/uv coordinates used on the model. If you use sharp edges, you need a lot more vertices to represent your model. A quick guess, assuming all your faces are quadruilateras, is that you are using around 27000 vertices - this still seems to be withing the limits, but it is close to it. (It is quite possible there is some internal OFP vertex buffer which imposes even stricter limit than 32K vertices).

I am to busy to provide you with a more detailed analysis, but I think this guess is likely to be close to the core of your problem.

[Indy 0]

ok now it's clear, but it's strange that it happens only with HW T&L activated.

Thx for the reply Suma