How to make clouds with normal maps?

PewPew · Feb 2012

Hello there. I'm doing some stuff to test around and I wanted to make a nice sky that moves around and whatnot. I'm looking forward to do something similar to Red Dead Redemption's clouds, which are affected by the light and they appear to have some depth.

What do you guys think would be the best way to do create the normal maps for the clouds? Sculpting it, maybe using certain images or something? Simple photo sourcing doesn't seem to be enough. How do you guys go about making it?

Also, I'm using still the November version of UDK if it helps.

I might post this on the Unreal Engine forums if nobody here knows, and link it. I guess someone else out there is also wondering the same!.

Thanks a lot for any help!.

Ace-Angel · Feb 2012

Not to sound arrogant, but stick to PolyCount or GameDev, UDK's forums aren't exactly a bustling hub of helpfulness in many cases.

As for the question, most clouds are made to fake Scattering properties, like Skin, Snow, Atmosphere, etc. Crysis does a good example of this.

Basically, create a Fresnel, and have it feed on an inverted Normal of your clouds, doesn't matter if you take Light or Camera calculation, both are valid for Fresnel in this case.

The edges of the cloud in question should be light and the inner parts dark.

PewPew · Feb 2012

Hey Ace-Angel, thanks for your help. I will try it out. I still have problems creating those fuzzy and "spongy" (?) clouds though. Dunno if I should just sculpt them or it would be enough with photo sources. I will keep trying over here anyway.

Really appreciated. As for the UDK forums, I didn't know it was so bad over there. I will still have a look, but yeah, there's a reason why I came here first :P (been lurking for a while!).

Again, thanks a lot for the suggestions.

Ace-Angel · Feb 2012

Alpha's would play an important role here for transparency, plus they need to be layered ontop of each other.

Did you take a look at UDK's clouds? They should give a good starting point. Since they're simply set on a sphere over ambient colors.

Other then that, in UDK, there are function, one of them is called Fuzzy, which is what you're looking for, try it.

PewPew · Feb 2012

Hey there again Ace-Angel. I have tried using nDo and it seemed to work fine enough to get the normals done. I took a look at UDK's clouds and yeah, they use fresnel (and many other things!). I'm testing it over here and it seems to work fine for now.

Thanks a lot and hopefully this might work as help for others out there!

Cheers!

How to make clouds with normal maps?

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