Ok 3 questions, Normals, AO, and UE3 Emissive
Hi there,
I'm pretty new to game asset creation so I'm tackling things I'm very much unfamiliar with. Hopefully someone is able to offer a bit of advice.
Firstly,
Is there a way to combine normal maps, and if so, what would be the best way to go about it. I'm trying to create a modular corrugated metal wall. I would like to combine the normal map from the high poly bake which gives a nicer bevel on the edges, then also the normal created from the diffuse because it gives detail on the worn/damaged areas from the diffuse. In this case, there isn't a whole lot of detail in the baked normal but it would be useful to know for any more complex model I do in the future.
Second,
I'm trying to bake an AO map in Max, and have run into a problem I've never seen before. The map looks like it's already been applied to a model with a grey diffuse if you see what I mean. It's not a white/black combination, it seems like the areas that should be white are grey. Is this simply down to a lack of light in the scene or am I doing something else wrong?
Lastly,
I want to create a translucent material in UE3 for a plastic warehouse roof, the kind you might see in an old factory. It doesn't need to be transparent in any way as I don't think the material would have any transparency from new, and in this case it will be old and covered in dirt. The way I'm thinking is to create my diffuse which will basically be a soft white dirt/grime, and use the same for the emissive. Obviously feel free to correct me if there's a better way.
Many thanks
I'm pretty new to game asset creation so I'm tackling things I'm very much unfamiliar with. Hopefully someone is able to offer a bit of advice.
Firstly,
Is there a way to combine normal maps, and if so, what would be the best way to go about it. I'm trying to create a modular corrugated metal wall. I would like to combine the normal map from the high poly bake which gives a nicer bevel on the edges, then also the normal created from the diffuse because it gives detail on the worn/damaged areas from the diffuse. In this case, there isn't a whole lot of detail in the baked normal but it would be useful to know for any more complex model I do in the future.
Second,
I'm trying to bake an AO map in Max, and have run into a problem I've never seen before. The map looks like it's already been applied to a model with a grey diffuse if you see what I mean. It's not a white/black combination, it seems like the areas that should be white are grey. Is this simply down to a lack of light in the scene or am I doing something else wrong?
Lastly,
I want to create a translucent material in UE3 for a plastic warehouse roof, the kind you might see in an old factory. It doesn't need to be transparent in any way as I don't think the material would have any transparency from new, and in this case it will be old and covered in dirt. The way I'm thinking is to create my diffuse which will basically be a soft white dirt/grime, and use the same for the emissive. Obviously feel free to correct me if there's a better way.
Many thanks
Replies
Don't know about your AO problem, perhaps read the article on my website to get some more insight into it?
UE3: not sure what you're asking, texture worklow? In any case, keep in mind Unreal doesn't have lit transparency materials...
I'm not sure what's up with the AO but it must be the geometry of the model, cranking the light intensity fixed it.
As for the Unreal mat, I've basically created an off plastic texture with a bunch of dirt and grunge on for the diffuse, desaturated it and adjusted levels very slightly and stuck it in the emissive slot. It seems to work well providing I want a kind of strong daylight look, although I was hoping for more of a SSS look which I think may be near impossible to achieve in UE in this case.
Again though, if there's a better way to achieve what I'm going for, I'm open to suggestion!
Thanks again
You could derive perhaps a better emissive texture/glow by using a little math, maybe a power node, mult, or just play around.
You don't want to use transmission (fake SSS) as it'll disappear as soon as you bake. For the record SSS is not impossible in UE3 either, they have a transmission slot which as far as I am aware, is the opposite direction to your light vector, or you can completely make a custom effect to mimic it.
And UE3 does support lit translucencys. Though it's more expensive, seems like a hack. You just set lighting model to phong, put diffuse info in to diffuse (not emissive, as you normally would for unlit translucencies) and then you have to bake lighting on the object. Won't be lit for dynamic objects but for what it sounds like you want, would work fine. But you should try avoiding it, as it is more expensive, and translucencies are always relatively expensive anyway
EDIT
Cliff notes then
Use a normal phong based material for this, unlit translucency isn't eally needed for it and nor is lit translucency. Create your diffuse as normal, with all grime on it and what not. Keep your grime on a seperate layer/group in photoshop though just incase.
Import your diffuse, plug it in to diffuse slot and then run a multiply of a scalar parameter through it, maybe, (so you can change the brightness of it on a material instance, just incase certain panels in your level are far too bright) and run the end result of that through a power node to heighten the contrast between your lows and highs. It can be an idea to make your diffuse's grime quite dark so it really pops when you run this through but its all a case of experimenting and finding what looks good versus what's useful for the best material quality.
All that is just theory though, and in reality it's hard to tell you what exactly to do without seeing your texture you are going to work with. But it is indeed possible to reuse your diffuse for other functions if you plan for it.
If you need any more help with it feel free to drop a PM
The level I'm working on is in fact just an env for my reel so playability and performance isn't an immediate issue so while it may be bad practice, I might try the translucency workaround you suggested. When I get to a suitable stage I will post a wip in the P&P forum and you can see what I mean.
Thanks again.
for combining the normal map. do u input 0-128 in the output or input in levels?
If you have the Nvidia photoshop plug in, you can just overlay one of the normal maps over the other, merge, and then tick normalize only on the filter.
tis how I do it.
Using Crazy Bump really is the best way to combine normal maps because it takes into account the actual directions of the normals being combined.
If you want to go the free route then that Project Offset action is probably the next best thing, it's much better than the overlay with a -50% blue channel method.