Ambient Occlusion with Alpha part 2
Posted Ekim 13, 2008on:
Now comes the real part. After adding this new map (ambient\reflective occlusion) to an empty slot, add this map to the self illumination slot to both the leaf materials (or any material having alpha in scene), make sure to use instance while dragging & dropping onto the slot .Turn off the color map and change the color slot color of diffuse to pure white.
Now add a new mental ray material to an empty slot with ambient\reflective occlusion map added to its surface slot (use instance) as shown below.
This new mental ray material with ambient\reflective occlusion map needs to be applied on to any other object in scene which is not using any opacity map. Once this is done, hit render now your render should look something like this as shown below.
At first instance the scene would look very noisy that’s because the sample rate under ambient\reflective occlusion map is default to 16, change this value to 128 which would make your scene less noisy as shown below.
The whole ideology for me showing this tutorial was imaging you has a huge scene with some 100s of materials applied to the objects & out of which 20 materials are applied to the plants or trees or any other object that has opacity to this. Using this method u can simply apply one ambient\reflective occlusion map to all the materials having opacity & make a new mental ray material for the rest of the object not having any sort of opacity. In one of my personal scene I had a real hard time getting ambient occlusion with alpha, using all the different plug-ins gave me lots of problems. But in the end I found this procedure to be very stable even in the bigger scenes without any errors or crashes .I hope it would be a great help to you guys also in making your scenes.
You can always reach me at charan [at] csgfx.com….
About the Author – I am 3d Modeler and Texture artist. Born and raised in India with Computer Science as my Background. I started 3d modeling in 3ds max in 2001 with strong will and devotion. I completed my Game Design course from Art Institute of Vancouver where I learnt various skills such as sketching, tetxuring, modeling and level designing.