Outerra forum

User mods, screenshots & videos => Other => Topic started by: ddenn on August 05, 2012, 06:19:04 am

Title: Experiments with modifying Outerra
Post by: ddenn on August 05, 2012, 06:19:04 am

I tried to make Cessna looks like it made of polished aluminum :

capture 1344160367 (http://www.youtube.com/watch?v=l-Of-loBBO8#)

Is this reflection texture procedural? I didn't find texture file.

Title: Re: Experiments with modifying Outerra
Post by: cameni on August 05, 2012, 07:39:42 am

There's no reflection texture, it's algorithmic and later it will use environment map generated by the engine dynamically. However, the lighting in the video looks wrong, saturates. The reflectivity must be too big or something else is wrong there. Angrypig will need to have a look.

Title: Re: Experiments with modifying Outerra
Post by: ddenn on August 05, 2012, 07:53:44 am

Well, if that be of any help, what I did is changed default material values in the c172.matlib file to this ones:

Code: [Select]


{
"name" : "Cessna_EXT-material",
"diffuse" : "1.0,1.0,1.0,1.0",
"Ax" : "0.99",
"Ay" : "0.99",
"m" : "0.01",
"tex_diffuse" : "",
"tex_normal" : "Cessna_EXT_norm.dds",
"tex_env" : "",
"tex_opacity" : ""
},

Tried different settings too, result was even weirder

(http://img836.imageshack.us/img836/2699/screen1344167280.jpg)

I get that with these settings:

Code: [Select]

{
"name" : "Cessna_EXT-material",
"diffuse" : "1.0,1.0,1.0,1.0",
"Ax" : "0.66",
"Ay" : "0.66",
"m" : "0.55",
"tex_diffuse" : "",
"tex_normal" : "Cessna_EXT_norm.dds",
"tex_env" : "",
"tex_opacity" : ""
},

Title: Re: Experiments with modifying Outerra
Post by: angrypig on August 05, 2012, 09:43:03 am

i am working on it...

Title: Re: Experiments with modifying Outerra
Post by: angrypig on August 05, 2012, 11:39:32 am

There were a few bugs that was causing issues with metallic materials. I never tested any metallic material so thanks for report. :)

I think you were looking for something like this but this will look much better once real environment reflections be there.
(http://i.minus.com/jh92CLGiZAvDk.jpg) (http://minus.com/lh92CLGiZAvDk)

I used these material parameters:

Code: [Select]

{
"name" : "Cessna_EXT-material",
"diffuse" : "0.025,0.025,0.025,1.0",
"Ax" : "0.91",
"Ay" : "0.04",
"m" : "0.15",
"tex_diffuse" : "",
"tex_normal" : "",
"tex_env" : "",
"tex_opacity" : ""
},

- diffuse has to be very low or zero because metals don't have diffuse only reflections and diffuse reflection is usually caused by corrosion or impurities...
- Ax is reflectance  and for usual material it should be in range 0.01-0.04 glass has ~0.08 and metals 0.3+
- Ay is not used so all our materials are isotropic, (performance reasons but may be i will implemented it later)
- m is surface roughness 0 means perfect mirror and 1 means mate material

It is possible to set Ax and m parameters through textures but this feature is not enabled yet. This will allow you to have more variations without raising draw calls count. In most cases texture with m is enough, it is similar to specular in alpha channel used in other engines but this parameter is more physically accurate.

Title: Re: Experiments with modifying Outerra
Post by: ddenn on August 05, 2012, 11:42:24 am

Thanks, looks very good!

Title: Re: Experiments with modifying Outerra
Post by: krz9000 on January 06, 2013, 03:09:43 pm

im starting to tweak some materials now for a car i imported...my question:

Ax = reflectance
m  = roughness

for me that is the same thing.
or is Ax = refraction?

modern materials often just use nd/ior and roughness to define reflection. with the roughness you get the "blurriness" between perfect mirror and lambertian and with the nd/ior you define the fresnel curve. a higher nd also defines the selfcoloring of a material e.g. high nd (like 20) high amount of reflection coloring like metals and low nd (like 3) for no colored reflection like plastics.

Title: Re: Experiments with modifying Outerra
Post by: angrypig on January 06, 2013, 04:35:42 pm

Here is a short description of our material system
http://www.outerra.com/xtrac/index.fcgi/wiki/material (http://www.outerra.com/xtrac/index.fcgi/wiki/material)

We will add more complex tutorial later...

Title: Re: Experiments with modifying Outerra
Post by: Bartolomeus on January 06, 2013, 04:41:20 pm

Thank you for the info Angrypig!

Marko

Title: Re: Experiments with modifying Outerra
Post by: KelvinNZ on January 18, 2013, 06:11:39 am

I should actually put this here, I had posted elsewhere but this seems more suitable

(http://i.minus.com/i5WwOQtWHT8L9.jpg)

(http://i.minus.com/ib1MSZb0IcH4ea.jpg)

This chrome looks quite amazing even without the env maps.

Title: Re: Experiments with modifying Outerra
Post by: traumstrand5 on February 12, 2013, 04:34:42 am

These metallic materials look pretty cool - can't wait 'til they look really cool, when OT is handling it properly. But even by now and already:
Looking very good!
Nice planes here as well!

Title: Re: Experiments with modifying Outerra
Post by: KelvinNZ on February 13, 2013, 03:21:03 am

Quote from: angrypig on January 06, 2013, 04:35:42 pm

Here is a short description of our material system
http://www.outerra.com/xtrac/index.fcgi/wiki/material (http://www.outerra.com/xtrac/index.fcgi/wiki/material)

We will add more complex tutorial later...

Looks like the file is unavailable.

Title: Re: Experiments with modifying Outerra
Post by: cameni on February 13, 2013, 04:08:32 am

Some parts were apparently renamed when we moved the tracker/wiki
http://xtrac.outerraworld.com/trac.fcgi/wiki/material (http://xtrac.outerraworld.com/trac.fcgi/wiki/material)

Title: Re: Experiments with modifying Outerra
Post by: KelvinNZ on February 13, 2013, 04:12:17 am

Thanks, I might just tack it into a document for my offline reference.