Mental Ray Lightning (Part 2)

Now the geometry is complete, but since we’re going to render the interior we should flip the normals of all the polygons:

1. Activate the polygon sub-object level
2. Select all polygons ( CTRL + a )
3. Go to the modify panel and click ‘Flip’ in the Edit Poly modifier ( Modify Panel > Edit Poly > Edit Polygons > Flip )
4. Deactivate the polygon sub-object level

Step 4 Creating Camera

Create a target camera ( Create panel > Cameras > Target ) in the top viewport and apply ( Make a selection > Modify panel ) the following parameters:

• Parameters
  • Lens: 20 ( wide angle lens is needed to get a good view of the interior )

Right-click on the Perspective view and press ‘c’ in the keyboard to change it to camera view. Move the camera inside the box to get a view like in the p

Step 5 Warehouse Material

Open Material Editor ( Press ‘m’ in keyboard ) and create the material for the warehouse:

1. Click “Get Material” button and select ( doubleclick ) ‘Arch & Design (mi)’ from the list ( Materials > mental ray > Arch & Design ).
2. Select the warehouse and assign the material to it.
3. Reflectivity: 0 ( perfectly matte surface )

Apply diffuse and bump maps:

1. Bump map: Composite ( Maps > Standard > Composite )
2. Add Smoke map to the first layer of the Composite Map ( large scale details )

   Size: 0,5

   # Iterations: 20

   Color #1: Black

   Color #2:
   Dark Gray ( RGB 50, 50, 50 )

3. Add second layer to the Composite map. Change the blending mode to Addition. Add Speckle map to the second layer ( small scale details )

   Size: 0,4

   Color #1: Light gray ( RGB 180, 180, 180 )

   Color #2: Black

4. Add this file as a diffuse map ( Maps > Standard > Bitmap > concrete-texture-high-resolution.jpg )

And here is how the rendered interior with default lighting looks like:

icture below.

Step 6 The Main Light Source

Now it’s the time to create the lighting. Let’s start with the main light source (sun). Create Mental Ray area spot (Create panel > Lights > Standard > mr Area Spot ) in the front viewport. Place the spot light according to the picture below. Modify the spotlight ( Make a selection > Modify panel ) according to the following parameters:

• Spotlight Parameters
  • Hotspot/Beam: 24
  • Falloff/Field: 26
• General Parameters
  • Shadows: On (Ray Tracted Shadows)

( Tip: If you’d like to make the light more directional, just move the spotlight farther away from the warehouse. )

Render the image to see the lighting:

Step 7 The Environment

At the moment we can’t even see the windows because the background color is black (by default). Let’s go to the environment settings ( Rendering > Environment… ) and change the background color:

1. Click ‘None’ and select Glow ( Maps > mental ray > Glow ) from the Material / Map Browser
2. Open Material Editor ( Press ‘m’ in keyboard ). Drag and drop the Glow shader from environment settings to an empty material slot in Material Editor ( make sure to select ‘instance’ when asked ). Make the following adjustments to the Glow shader:

   Glow: White

   Brightness: 4

Render the scene to see the effect:

Now that we can see the windows, let’s apply a glow around them. Apply Glare Camera Shader ( Rendering > Render Setup… > Renderer > Camera Effects > Camera Shaders > Output > Glare ) Just turn the output shader on, the glare shader should be selected by default. Render the image again to see the difference. ( The use of Glare shader is the reason for using Glow shader in the background instead of just white color. )

(The glow effect might seem really strong at the moment but in my opinion it works well in the final image. You can adjust the strength of the glow by adjusting the brightness of the glow shader or by adjusting the glare shader itself.)