SSmolak wrote:Corona scene attached. Octane is a winner here too.
In this example the "windows" are dark in Corona and white in Octane, which will reduce the amount of light reaching the extrusions a lot in the Corona render. So it's not a fair comparison.
In general think of it this way: If you look at a point on a perfectly white diffuse surface, try to "imagine" how much light can arrive at that point from all possible directions (spanning a hemisphere around the normal of that point). If the light from all possible directions is white (or 1), then the point will be shaded as white. If light from all possible directions is only 50% grey, then the point will be shaded as 50% grey. If the light from one half of the hemisphere is say 20% grey and from the other half say 60% grey, then the point will be shaded as 40% grey. Now if your surface is not perfectly white, then things get darker accordingly.
Another thing to keep in mind with exterior renderings is the contrast between the sky and the sun. Usually the sun is really bright and the sky is not. So unless your ground has a very light colour, any surface pointing down will be very dark compared to surfaces facing the sun. You can reduce the contrast by increasing the sky turbidity. But that goes only so far as the sun is really really bright.
In theory there is no difference between theory and practice. In practice there is. - Yogi Berra