fog above surfaces

[dlefik2008]

hi all, just learning the ropes with terragen still yet, but happen to wonder how i would go about doing a layer of fog above surfaces. for example, if i had a scene with a lake and i wanted to do a thick or thin layer of fog over just the water surface, how would i go about doing that? just experimenting, i decided to try and use the haze and lower the ceiling and height, which worked good, but then sucked the blue right out of my sky once the haze got so low to the ground. so i'm thinking that approach was a no go.

keep in mind i've only been working with terragen for a few days, so if it's some really complicated process, i may have a hard time following, but i will certainly try my best.

[schmeerlap]

Create another cloud layer (maybe Altocumulous is best) and adjust its altitude to just above your lake. Then go to the cloud's Density fractal and in its Blend by Shader option insert a Distance Shader. Go to that Distance Shader and set its Distance mode to Spherical. In the Camera slot add a new camera and position it in the centre of your lake. You'll contain the cloud by adjusting the Near and Far Distance sliders.
Hope you don't find that too complicated. If you get stuck, holler.

John

[cyphyr]

Just add a Low Level Cumulus (3D) and set its height to say 10m above the water level and adjust the cloud depth to twice the height above the water, in this case 20m. Try to avoid the cloud layer actually intersecting the water as this will increase the render time further and you may have to increase the cloud density to compensate for the thinness of the layer. A point to note here is that volumetrics interacting with reflections is going to be very slow, enabling Ray Trace Shadows will slow the process down a lot more.
Good luck
Richard

ps agree with schmeerlap, mine is just a slightly different take

[dlefik2008]

cool, sounds good guys. i'll give it a go and see how it turns out. doesn't really sound complicated at all. thanks for taking the time to step me through it.

[Viktim]

Create another cloud layer (maybe Altocumulous is best) and adjust its altitude to just above your lake. Then go to the cloud's Density fractal and in its Blend by Shader option insert a Distance Shader. Go to that Distance Shader and set its Distance mode to Spherical. In the Camera slot add a new camera and position it in the centre of your lake. You'll contain the cloud by adjusting the Near and Far Distance sliders.
Hope you don't find that too complicated. If you get stuck, holler.

John

wow, i have read many threads about the distance shader and have never understand what it really does and when/how to use it. This was a very good explanation, thank you!

[choronr]

Thanks John and Richard for both explanations. I do something a little different; but, it is good to try these next time.

[TheBlackHole]

Create another cloud layer (maybe Altocumulous is best) and adjust its altitude to just above your lake. Then go to the cloud's Density fractal and in its Blend by Shader option insert a Distance Shader. Go to that Distance Shader and set its Distance mode to Spherical. In the Camera slot add a new camera and position it in the centre of your lake. You'll contain the cloud by adjusting the Near and Far Distance sliders.
Hope you don't find that too complicated. If you get stuck, holler.

John

Blend By Shader? I usually use a Multiply color node, with the same results.