Digital Foundry Article Technical Discussion Archive [2011]

[Rotmm]

(Blue car should show a reflection of player's car passing by ?)

If it's anything like Forza 3 (and I suspect it is), then no cars reflect other cars (only the environment) and that includes the players car. In fact, the only time other cars are reflected is when using the hood-cam or in-car view.

 

[Karamazov]

in gt5 every car has the cube map of the player's car, so if the player's car is in a tunnel, it will reflect the tunnel, et AI cars even those which are outside will reflect the tunnel too.

 

[kagemaru]

Gaffers are also saying the AI cars don't reflect the environment dynamically (or perhaps use a simplified method).

e.g., http://www.abload.de/img/forzamotorsport4_careeh7bj.gif

(Blue car should show a reflection of player's car passing by ?)

Am I guessing correctly that you read this Gaffer comment (and maybe gif) in that joke Forza vs GT thread? Unless someone is new to Forza, I would think most of the regular players would know how the reflections worked in both F3 and 4.

in gt5 every car has the cube map of the player's car, so if the player's car is in a tunnel, it will reflect the tunnel, et AI cars even those which are outside will reflect the tunnel too.

I could be wrong, but I believe the same thing happens in Forza as well. The big difference between the player car and AI is the reflection of other cars which is only visible in the hood cam or cockpit views anyways.

 

[Reiko]

I was wondering, GT has had it right since GT3, as best they could on the hardware. Is there some formula that they've developed for car shading and this is used, or is it artists having to work every model somehow? I'm thinking there must be a guy/some guys at PD who came up with the car-lighting-formula they use and it should be reproduceable. Offline car renders are easily photorealistic. Have PD just managed to simplify the techniques effectively so it looks convincing in realtime?

I guess like Coca Cola and Heinz Beans, the secret ingredient will never be known!

Color and texture choices are the most apparent. It's also strange how Bizarre Creations has also managed to nail that photorealistic look with PGR4. Instead of striving to match GT5, they should build off from PGR4's look and start up from there.

 

[patsu]

If it's anything like Forza 3 (and I suspect it is), then no cars reflect other cars (only the environment) and that includes the players car. In fact, the only time other cars are reflected is when using the hood-cam or in-car view.

in gt5 every car has the cube map of the player's car, so if the player's car is in a tunnel, it will reflect the tunnel, et AI cars even those which are outside will reflect the tunnel too.

I see. I'm just starting to get into GT5 online after playing just special events. Will check the effects out.

EDIT:

Am I guessing correctly that you read this Gaffer comment (and maybe gif) in that joke Forza vs GT thread? Unless someone is new to Forza, I would think most of the regular players would know how the reflections worked in both F3 and 4.

I read that thread once in a while, but also got questions from folks in the chatroom. I don't think B3D is that different from GAF sometimes. ^_^

 

[AbbA]

I think a Scorpio black would be less expensive & a wiser choice. Sure SSD will make the game run perfectly, but I think the jump to the 5400RPM HDD to a 7200RPM HDD will likely fix to a very acceptable level.

Rage on Ps3 with HD 7200 16MB
http://www.youtube.com/watch?v=ecu1Yr0WljE&feature=player_embedded

 

[Reiko]

I see. I'm just starting to get into GT5 online after playing just special events. Will check the effects out.

EDIT:


I read that thread once in a while, but also got questions from folks in the chatroom. I don't think B3D is that different from GAF sometimes. ^_^

Well I made I comment on that, but I forgot where I am. This IS a tech forum afterall.

ON TOPIC:

I think the reflections being taken off of the cars were strictly performance related (obviously). Turn 10 still went wild with their environments.

So looking at both games in the future we should see them having:

Equal detailed environments with the photoreal edge going to PD. (Unless Turn 10 rehauls the textures and makes them more photorealistic than Forza 4)

Equal LOD distrubution

Premium/Autovista detail for all cockpits

Stable framerates

All the pluses of GT5's visual accomplishments none of the blemishes.

Now the lighting set up for the future titles is most interesting. A Fully Deferred Renderer for a Racing Sim?

 

[_phil_]

Is there some formula that they've developed for car shading and this is used, or is it artists having to work every model somehow?

For the car paint , they Use a custom shader with 1d lookups to reproduce a mesured BRDF of each car.
They used a spectrophotometer to capture light/car paint behavior at various incidence angles.

For the headlights ,they have a primitive-based raytracing shader .For reflector interreflection and lens refraction.

 

[Laa-Yosh]

Now that explains why it's so nice and fast enough for 60 fps at the same time... thanks!

 

[3dcgi]

For the car paint , they Use a custom shader with 1d lookups to reproduce a mesured BRDF of each car.
They used a spectrophotometer to capture light/car paint behavior at various incidence angles.

For the headlights ,they have a primitive-based raytracing shader .For reflector interreflection and lens refraction.

What do you mean by primitive-based?

Thanks.

 

[tabs]

Presumably basic shapes rather than complex geometry. Cube, sphere... ?

 

[_phil_]

Presumably basic shapes rather than complex geometry. Cube, sphere... ?

Exactly.
Sphere and parabole,in fact.
I still think the visual qualities of the gt games are ultimately artist driven.A really good eye .

 

[AbbA]

LOD in everywhere on forza4

http://makeagif.com/media/10-19-2011/vpPbaq.gif
http://makeagif.com/media/10-19-2011/wjDodT.gif


http://pic.phyrefile.com/c/cr/crazyrussian540/2010/11/22/lunapic_129041089112991_1.gif

 

[AlNom]

Folks, this isn't a versus discussion.

LOD in everywhere on forza4

http://makeagif.com/media/10-19-2011/vpPbaq.gif
http://makeagif.com/media/10-19-2011/wjDodT.gif

Yes, there are differences between Time Trial and regular game play, not just 4xAA and 2xAA.

 

[Tea2]

Any guess on how many polygons those Time Trial car models have? Are those menu-quality level models ?

edit: Looking at the data mined from Forza Motorsport 3 that would be around 170k polygons per model. Something in that ballpark?

 

[Reiko]

Any guess on how many polygons those Time Trial car models have? Are those menu-quality level models ?

edit: Looking at the data mined from Forza Motorsport 3 that would be around 170k polygons per model. Something in that ballpark?

Those ARE the menu models during that mode.

During chase cam you can see the full detail in the cockpit with all of the reflections.

Also the menu models are used for the replay in that mode.

 

[Kasersky]

hopefully this doesnt sound like a vs post im trying to speak more about the artistic approaches...

i think its an issue of visual consistency when people look at forza4. for example that little dirt patch looks great but then because of poor filtering a similar dirt patch ahead loses alot of detail.
http://images.eurogamer.net/2011/articles//a/1/4/1/1/1/9/0/360_009.jpg.jpg

GT on the other hand visually is more consistent all track detail is sort of a wash but this lets our minds fill in the detail because nothing in particular stands out.
http://images.eurogamer.net/2011/articles//a/1/4/1/1/1/9/0/PS3_009.jpg.jpg

thats the thing side by side forza4 wins in detail but when we talk about realism i think visual consistency is what our subconscious equates to realism.

edit: has anyone seen this? is this what the power lines look like in game?
http://images.eurogamer.net/2011/articles//a/1/4/1/1/1/9/0/PS3_018.jpg.jpg

 

[Laa-Yosh]

So let me check if I get you right - worse is actually better?

 

[Nesh]

edit: has anyone seen this? is this what the power lines look like in game?
http://images.eurogamer.net/2011/articles//a/1/4/1/1/1/9/0/PS3_018.jpg.jpg

Wow I have never noticed that to be honest. They are so ugly its as if they were drawn on MS Paint. Need to check it myself

 

[AlNom]

Weird... must be a bug or something. That's something that 4xAA should have fixed.