Quick tip #3 - VRay Fog

Hi everybody .. this is josef again with another quick tip ..
QT Files Cinema 4D
Before you continue please note that these are only my personal views and experiments and some info I gathered reading vrays manual and some tutorials via Google

So Today we are going to talk about something I find very exciting ( Vray Fog ) .. now we all know what is exactly fog is .. but we still can use this feature for other kinds of things like smoke ,clouds, dust and even haze !

Super .. now that we know what to use it for .. Let’s take a look at it

Now you have to admit that this isn’t a good interface look for THIS feature ( scatter ? density ? emission ? ) .. But once you get your hands on it.. It’s quite easy actually

Let’s start simple and say.. The top 3 important things that you should pay attention to are    
1-Fog distance   2- Fog height    3-The gizmo and light boxes (to include lights and gizmos)

But before we talk about these .. let's see our scene setup first .. the first thing you notice is that I used a large sphere (with a texture tag on it) as a gizmo for my fog .. and this simply I didn’t wanted fog the everywhere in my scene .. so the sphere acts like a container for the fog .. I could use the fog height instead but I tend to use this method, also I have the spot in the lights box . And also note the intensity of light (10W) which is a bit high, fog distance is set to 300 which we can call it thick !

Let’s go back to the 3 main parameters and start with fog distance

Fog Distance: is the parameter that controls the density of the fog (or thickness in plain English) smaller values tend to make the fog more dense causing the light rays to move (or fly) slower in it , while larger values tend to make the fog more transparent (or lighter) causing the light rays to move faster in it !

What about the Fog height?
Fog height: can be used instead of gizmos but if there was any gizmos in the gizmos box .. this one is automatically ignored

The last thing which are the gizmo boxes and light boxes.. I think you already know what they do .. :)
You can play around with the tow scenes I provided to see how I have used the other parameters... But I think also you should pay attention the subdivides parameter which can make your rendering cleaner and noise free.. Also note that although GI scatter can make your rendering very slow .. it could be useful in many cases as well !

Oh yea .. one more thing .. you should always use a texture tag on your gizmo's .. this is just to let vray know or realize the UV coordinates of your object (don't really know if its necessary but this came out on forum 
I think this it for today .. and I fell like we might need a second part for this ..but anyways take care :)

P.S : You should use the texture tag for you objects all the time when using them with VRay fog .. the porject files are made using R11 so if the fog not working fine .. chick the objects if they have texture tag or not


Anonymous said...

Thanks Josef for that!
1 Problem: In the "Gizmo on sky" file, there is a noise texture in the density slot. it doesnt work. Even if i scale the Global Size . When i delete the noise, everything is fine. How is the correct settings for the noise, to get the effect like it is shown on your example?

Cheers Hiro

josef bsharah said...

Hi hiro .. thanks for commenting .. am still using r11 and the texture tag was no big deal .. i just tested it with R13 and you should add a texture tag to the "Torus" objects to see the fog working fine .. thanks

post updated

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