Improving the shadows

To the right is the render as we basically left it last time, right before discussing shadow properties and types.

The light setup is 5 lights of 15cm in diameters, just large anout to encompass the chandelier's modeled light bulbs. The light have a slightly redish color, is casting a 8)5 darkness raytraced shadow with one ray casted.

We examined the effect of changing the light width on the shadow quality. But we know that the light width in this scene should be set so that it just encloses the chandelier's modeled light bulbs so a diameter of 15cm is suitable. Using much larger diameters than that could help simulate the diffuse light that is bounced by the supposedly white ceiling but we would loose the individual chandelier light shadows and seeing individual shadows is a shadow effect that can add realism. We do not want raytracing sharp shadows though.

We now need to improve the shadows. The first thing to do is set the shadow darkness to 100%.

Recall that we added an ambiance color to the choreography so we will no get black shadows. The shadows are much more obvious this way but they still should be even more obvious.

One aspect of the shadows that is bothersome is that the shadow on the front of the chair seats are much darker than the shadows on the floor. In fact, the shadows on the floor could really be improved.

As we have observed in a previous page from this tutorial, when using single ray cast shadows, A:M tries to simulate ambient lighting by calculating a shadow falloff. That is the shadows are reduced in darkness as the distance from the shadow casting object increases. The only way to get our shadows back to full darkness is to cast more than one ray for shadows and use multipass.

In the render at right the Chandelier light is casting 16 rays and the "Distribute in Passes" is set to ON. This means that the light will always cast at least 16 rays no matter the number of passes used. This ensures that we always get nice soft shadows (in A:M version previous to v14, set the ray cast property to 2 and use 9 passes multipass to get 18 shadow rays).

Because the number of rays casted for shadows is higher than 1, the shadows are now much more darker and can be better controled by the "darkness" property. In this render, the darkness is still 100% but the shadows are still not totally black due to the added ambience color in the scene.

We have pushed this render quite far without adding any more lights in the scene so we managed to add more realism in the lighting without dramatically increasing the render time.

Next, we will examine how we can add even more realism without radiosity but by adding bouncing lights.