Multipass rendering in 3dsmax
When you render your scene in passes it gives you the flexibility to modify the elements in the scene. You can adjust shadows, lights , specular , reflections anytime in a compositing software as per your need.
Basic Render Elements
Ambient Occlusion – This is not a pass but a shader which can be included as a pass. Use this shader to get contact shadows.
Diffuse pass – It is the flat renders of all colors in the scene. It contains only textures.
Lighting pass – It renders only direct and indirect lighting. Key light , fill light , rim light are rendered in different passes.
Reflections pass – It renders the reflections in the scene.
Self illumination pass – It renders the self illuminating materials in the scene.
Specular pass – The specular component of rendering. Can be additionally used for blooming.
Matte – Perfect black and white images can be used for masking.
Z-depth pass – It is used for depth of field and color saturation based on depth.
Setting up your scene
- Before you start to render the passes, make sure you complete the texturing and everything in the scene is final.
- Place the lights in scene. Turn on/off the shadows as needed.
- Setup camera and create a nice composition. And save the file as Main.max.
Render Passes
Ambient pass
- Change the renderer to mental ray.
- In an empty material slot make mental ray material and under basic shader select ambient/reflective occlusion (base)
- Set the sample value and max distance as needed.
Apply it to entire scene and render it. Save file as AO with file extension .tga.
Matte , Z-depth and Diffuse
- Open Main.max file.
- Open Render dialog and go to render elements.
- Click the Add button and select Matte,Diffuse and Z-depth.
- Hit render
Specular Reflection Lighting
- Open Main.max.
- Open Render dialog and go to render elements.
- Click the Add button and select Specular , Reflection and Lighting
- Hit render.
- Follow same steps for Shadows and Refraction.
Compositing
Diffuse Pass – Set blending mode to Normal.
Lighting – Set blending mode to Screen or Multiply depending on the scene.
Shadows – Set blending mode to multiply.
Ambient Occlusion – Set blending mode to Multiply or Overlay depending on the scene.
Reflection – Set blending mode to Add.
Specular- Set blending mode to Screen.
- Put z-depth in adjustment layer.
- Adjust the opacity of layers till you get the desired result.
Thanks for reading. Comment below if you have any questions regarding this tutorial.