What is most important for FPS, texture size or model?

[swimeye]

This may be a little off topic but i am curious about this topic and you guys and gals seems to know alot so here we go:

If i have a large texture on my AI aircraft and a very high polygon model, which causes the biggest impact on my framerates? Is it the high poly model or the hig res texture?

Thanks for reading.

BR

[Firebird]

I think that its best to wait for a definitive answer from somebody that has experience in creating models, but this is how I understand it.

The size of the texture will affect fps, the format of the texture will affect fps, the number of textures will affect fps. As for the model the more polys a model has the more the rendering engine has to work and the more it affects fps.

The biggest issue is probably whether a model contains LODs or not (Level of Detail). To try and explain this simply if you have a model that is made up of 56,000 polys FS will have to render all those polys no matter whether you are within 100' of it or 10 miles away from it. If you build in LODs you are basically reducing the quality of the model the farther away from it that you are. Less quality means less polys, which translates to quicker rendering.

This fact leads us onto the next point. If you have no big scenery demands and no other objects a 56,000 poly model at 10 miles may not have any significant impact on your system. Likewise a 5,000 poly model would have far less impact, close up and far away. However, you have an air base with one hundred 5,000 poly models its going to have a bigger impact close or far away, the PC has to render 500,000 polys a frame.

Therefore compromises have to be made, we limit the number of polys on our models to start with and then apply LODs so as to limit the affect that multiples of the model will have. We also keep the texture to the smallest size that is realistic and try to keep to one texture, if possible. The experience we have gained tells us that the biggest affect on fps, is not necessarily an in individual model but the whole picture that you are having rendered in front of you.

Now after waffling on in general terms, I shall try to be more specific to your individual case.
Taking into account that everything has an impact and without knowing the exact details of the textures and model, its probable that the polys will cause the greatest single impact, close up, but after a couple of hundred feet not having a model with LODs will probably be causing you the biggest impact.

I hope this answers your question, and I hope that I haven't got any point wrong here.

[Graham King]

I think the answer is the polys. When using a normal B-52 model I think the limit was about 4 aircraft before the fps became unacceptable.

[nickblack423]

Well if you remove all the textures from your AI aircraft you will notice that you still lose FPS because the actual objects need drawing by FS....add the textures in again and they drop even more, even more for aircraft that have multiple large texture files, like user aircraft.

What we do here is create Low-poly aircraft that have simple single file textures...this way we make it as easy as possible for FS to draw the aircraft.

Nick

[swimeye]

Thanks for your answrs, very interesting.