Ambient Occlusion maps

Rendering out an Ambient Occlusion map and adding it on top of your beauty pass adds a lot of definition. It’s a great technique to learn and is very simple to do. If you’re wondering what an ambient occlusion map looks like, it is one of these:

3DS Max AO Map

As you can see, an ambient occlusion map creates a white image, with dark areas. These dark areas represent all the cracks and crevices in your scene, creating the shadows for these areas. You can then place this map over your beauty render to add depth and realism to these areas. In this post, whenever you read AO, it means Ambient Occlusion.

The video above shows the result of the scene when enabling and disabling the Ambient occlusion map. It’s quite a poor example, however it does it’s job of showing what AO does. Now lets look into how to create your own AO map and add it to your original render. There are two methods you can use, but we’re going to go through the easiest one.

Tutorial

I have included a gallery below which accompanies the tutorial, I have also included a short YouTube video which shows me going through the process.

  1. Start by going into your Render settings, and heading over to the “Render Elements” tab. Ensure you have your renderer set to VRay in the Common tab.
  2. Ensure that the “Elements Active” box is checked, then click the “Add” button.
  3. Scroll down a little and look for “VrayExtraTex”, select it so it is highlighted and then press the OK button..
  4. You’ll be back in your render elements window now, scroll down to the bottom where you will see the “VrayExtraTexParamaters” box. You’ll see a box that says “None”, click it. In the new window, search for VrayDirt, and double click the option that shows up.
  5. The window will close. Go into your material browser (pressing M), and drag the box that said “None” (it will now have a different name in it) into one of the material slots.
  6. Edit the radius on the material, this may take some testing. I did 75 which worked first time. You can also increase or lower the subdivs to get a higher quality AO pass.
  7. You can now render. In the top left of the render window, you will see a drop down. You can switch to VrayExtraTex to see the result. It will only show up once it has completed rendering, so don’t worry if the screen is black at first. Save out your textured render AND the AO pass as separate files.
  8. In Photoshop, you should import your textured render, and then place the AO Render on top of it. Change the blending mode of the AO pass to “Multiply” and adjust the opacity to something that looks right.

In the video above, you can see my final result. You can see how all of the edges and crevices are more defined and darker.

 

 

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