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reflective textures on buildings useless ?!?

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I just did my first reflective textured building with gmax. I wanted to reproduce the shiny glass effect you get when the sun shines on a glass building.I found that the reflective alpha channel doesn't make your texture reflective, but rather blends a grey reflective (metallic) colour over the opaque texture. If you use a low alpha value (lots of reflection) you end up with a chunk of iron/silver with a faint look of your texture. So, you are limited to a high alpha value, which doesn't give much reflectivity. All I get now is that the building looks a bit brighter when I get closer, but that's all. In the end all I could do is just brighten up the texture, and I don't get the popping effect, since it seems that only the largest mipmap uses the alpha channel (maybe I have to use my own mipmaps each having an alpha channel...).In the end I'm unable to reproduce the glass reflection effect, so I wonder what is the use of using reflection textures at all (on buildings that is, on planes the metallic look is ok)... In the end it seems to me that reflective doesn't mean true reflection (shinyness), but rather 'metal look' in FS2002. That is only for textures, because for materials this works fine (but who wants to have untextured buildings...). Cheers, Christian

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You are right I am afraid it will be a while before hardware will beable to handle ray tracing in real time,(the overhead in computing a"real" reflection is huge) and then to animate one at the same timeis simply far too much for any consumer level video card to handle.Heck it's real hard for a SGI work station with a dedicated graphicssubsystem to do raytracing in real time and those sub systems can cost 15,000 dollars U.S. One thing you might try is to add a "mesh smooth" modifer to selected parts of your mesh(if you are using gmax)What that will do is change how the mesh "handles" how each face is"lit" by the lighting in the scene.(Be sure to leave "itinerations"set to 0 so you don't add unessary poly's).Hope this is of some help.

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I wasn't talking about 'real' reflections! I'm complaining that it seems like FS2002 doesn't treat the alpha channel as reflections like I'm used to it from modelling programs. Ie I can't reproduce the effect you can see in the gmax help pictures under the entry 'highlights/specular'.Firstly, we don't seem to be able to specify the highlight (specular) colour for the reflection.Secondly, it seems to me as if all faces get treated the same way, ie a light source that creates the shininess effect is simply missing. In other words, only the sides facing the sun should be shiny, but the sides in the shadow get treated the same in FS2002...Thirdly, the shininess doesn't map onto the texture correctly. I either get a massive grey shiny block with barely any texture on it (and all 4 faces look like that!), or I have to tone the alpha channel down, so the shininess isn't visible anymore.To summarise, with textures on rectangular buildings using reflective material doesn't seem to make sense. I can't reproduce the 'shininess' I get in reality when the sun shines on a glass building...I'm just wondering if I'm doing something wrong or if FS2002 just isn't able to mix textures and specular colours in a realistic looking way... I'll try the 'mesh smooth' option, but I just have a 4 sided block, so the vertex normals should be fine...Cheers, Christian

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No problem sorry that missunderstood what you wanted you might want to tesselate the side(s) an itineration or two as that will give you a few more normals for the sim to play with and detach so that the entire mesh does not get meshed smoothed (but do not move the above poly's I will attach a pic take a look at the roof it's the "best" I've been able to come up with. It does seem to give a sheen but that's all. ( P.S. I hope you can see the effect) Dan

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Thanks, Dan.I think I can see what you mean in the screenshot.Some questions:If I just use a standard box primitive in gmax, does FS2002 actually gouraud shade it (now wonder I can't see the effect then!)? On the other hand the shading seems right, it's just the reflectivity that's seems wrong...What percentage do you use for the alpha channel (I used 10%, because with 50% the texture is too faint...)?Do I have to edit the normals by hand then? That'll be interesting, haven't done that one beforehand...Does the reflection change noticably as you move, or could you basically achieve a very similar effect if you just would have brightened the texture in photoshop?Do you get the reflectivity popping in and out of view, depending on how far you are away (I suspect my mipmaps don't have the alpha channel).Can you set a highlight colour?Many thanks, Christian

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Duh one could achieve that in Photoshop as well but I don't thinkyou would get the sheen to follow the envirorment mapping. 2nd I use Blinn shadeing not Gouraud shadeing so that may make a diff. 3rdbeleve it or not I hardly ever use mip-maps( can't stand the way F.Shandles mipmapping on objects and I still get great frame rates BTW)4th All my models are from extruded splines not from any "pre-made"objects as I have far more control over my final mesh that way. If Iremember right I think I set the alpha to about 15% or so. As for howFS shades good question with out an sdk I can't tell you! but from what I understand Blinn shadeing seems to be the most common for gameing(I am not a real code head BTW)so I may not really know.Oh since I don't really use mip mapped textures very much I don't get textures "droping out" Jim and I have come up with a few tricksthat work to prvent smaller ojects like runway signs from looseingtheir textures. Last try playing around with the gizmo when in mapping mode the angle that a texture is applied relitive to the poly is important as many people do not understand how mapping reallyworks as you know you can't allways just stick a texture on a meshoften one has to play around with the "angle of projection" via theUVW editor while in mapping mode and not in unwap as unwrap is really 2D not 3D. Hope this is of some help

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Hi Christian,I have also done some testing with the reflective textures. I think basically it looks nice. I am still trying to find out which alpha channel values give the best result, as it also depends on the where the sun stands etc.Here I have a picture of one of my objects with and without the reflective texturing.http://home.wanadoo.nl/arno.gerretsen/pics/ref.jpgAnd if the user doesn't like the effect he (or she) can always turn it off in the preferences.Arno


Member Netherlands 2000 Scenery Team[a href=http://home.wanadoo.nl/arno.gerretsen]http://home.wanadoo.nl/arno.gerretsen/banner.jpg[/a]

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Hello,Sorry to enter your conversation. Do you have both the transparency and the reflexion with your tower windows ? I though it was not possible to have both at the same time !! (Microsoft materials usage documentation).FLorent

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You can get that effect by setting the transparancy in the material editor. The entire material will then become transparant and you can use the alpha channel for the reflection. This of course means that you will have to use seperate polygons for the windows.Arno


Member Netherlands 2000 Scenery Team[a href=http://home.wanadoo.nl/arno.gerretsen]http://home.wanadoo.nl/arno.gerretsen/banner.jpg[/a]

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It does make sense. So only transparent texture using alpha chanel can't do refexion at the same time.Florent

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