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Contents 1 Creating and Using Reflection Maps 1.1 Add the Parameters 1.2 Set the Parameters 1.3 Render the Environment Map 1.4 Houdini 8.0 Example Scene

Creating and Using Reflection Maps

Creating reflections maps is very easy with Houdini.

Add the Parameters

In Houdini 9.0+, you will need to add the following RenderingParameters to any GeometryObject or NullObject in your scene:

• Auto-Generate Environment Map (render_envmap)
• Pixel Samples (vm_samples)
• Output Picture (vm_picture)
• Resolution (res_override)

Set the Parameters

Turn Auto-Generate Environment Map on, edit the Output Picture parameter with your destination filename (eg. my_environment.rat). The Resolution and Samples will control the quality of your environment map.

Render the Environment Map

Like with ShadowMaps, the EnvironmentMap is generated at render time by mantra so to generate one, just perform a render. You can now use this environment map in reflections or as an environment area light map (in the LightObject).

Houdini 8.0 Example Scene

(Please Note that the Houdini 9.+ workflow is significantly different)

Please download the hip file which is referred to in this page. In the hip file, there are two objects, tube_sphere_box and environment so go to the tube_sphere_box object's Shading tab and turn on Auto-Gen Reflection Map. We will use the default Map Name parameter.

Once done, please create a new Light & rename it to reflection_map_light. Under the reflection_map_light's Shading tab, edit the Reflection Map parameter to be $TEMP/tube_sphere_box.rat. Before rendering the next preview, please turn off the tube_sphere_box object's Auto-Gen Reflection Map toggle and also turn off the Display flag of the environment object. You should get the following image:

To control the intensity of the reflection map, there are two methods. The first method is to adjust the light's Dimmer value so change the reflection_map_light's Dimmer to 0.5 and render. The second method is to adjust the specularity of the object. Go to SHOPs, select the v_plastic1 shader and change the Specular value to 0.5 and render. Notice how the tube_sphere_box object gets less reflective with each render?

To turn off reflection mapping for certain objects, edit the Light Mask parameter of the objects to exclude the light projecting the reflection map.