God Rays - troublesome

[DarcTheo]

Playing around with a foresty scene and trying to get some volumetric fog for a bit of god ray play. Really struggling to get any kind of defined ray. It's always looking like a very big blur of fog or a lack of fog.
The only way i get a defined ray is to point the sun toward the camera and then block it with a tree, however i do not want to point the sun at the camera.

I've attached an image from a tutorial i followed, except my results are very different. Im not sure if its just my setup that wont work very well but i tried using a box with holes and shining light through the holes and that did the same, there was lack of contrast from light and shadows with the fog. it just lightly mists over everything.

Anyone got some time to help me define these rays a bit more?

edit scene is in cm :) and roughly spans across 10,000 cm if that helps with material stuff

[maru]

Here are some tips:
-disable environment lighting, leave sun only - this will exaggerate the godrays, the contrast between godrays areas and no-gordays areas is based on light intensity, so if sun is much stronger than skylight - the rays will be more obvious
-enable interactive renderer - it is extremely useful here
-play with directionality parameter of the fog material - values between 0,5 and 0,8 should make the rays much more apparent

[DarcTheo]

Here are some tips:
-disable environment lighting, leave sun only - this will exaggerate the godrays, the contrast between godrays areas and no-gordays areas is based on light intensity, so if sun is much stronger than skylight - the rays will be more obvious
-enable interactive renderer - it is extremely useful here
-play with directionality parameter of the fog material - values between 0,5 and 0,8 should make the rays much more apparent

I'll give them a go, i tried to use IR but it just gave me a white screen.

so IR worked in the frame buffer just not in view port. using just a sun also helped and reducing the amount of spots for light to come through also helped a bit more. just a matter of tweaking from now i guess. at least i can see something more defined!