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Month: December 2023

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Week 9 – Rendering in Maya

Rendering is the process of exporting your 3D models into image files. In Maya, you have the flexibility to choose your preferred renderer. While there are paid options like Redshift and Octane, Maya provides Arnold renderer by default. You can explore the pros and cons of different renderers online to select the one that aligns with your preferences. In this class, we learned about the Arnold renderer.

Set three Area lights
Rendered image
Light settings

Before initiating the rendering process, adequate lighting is crucial for the scene, otherwise, you’ll end up with a black screen. Arnold offers various lights, including Area lights, or you can use the default lights such as directional or spotlights. For a fundamental understanding of lighting, you can refer to Gonzalo’s class. The key, fill, and back lights can be adjusted in terms of intensity, temperature, exposure, and more.

During work, if you want to lock some objects that you cannot click on, go to Channel Box/Layer Editor-Display-Layers-Create from selected layer, and Click a box beside ‘P’ letter. It will change to T (lock with Wireframe view), and press it again; it will change to R (Lock).

Set HDRI image

To facilitate work in a VFX scene, achieving a match between the 3D scene’s lighting and the filmed scene is crucial. Using HDRI images (you can get a lot of HDRi images for free at HDRi Haven) can help emulate real-world lighting conditions.

  • Follow this steps to apply a HDRI image: Arnold-Lights-Skydomelight-Color(click checker button)- Select File on Create Render Node-Import HDRI file
Set ‘Camera’ value to 0 when you want its invisibility

You can check if your objects reflect HDRI information such as reflection, light intensity, and color. If you want to render without the HDRI in the background but retain its lighting and reflection effects, set Visibility-Camera to 0.

Rendered with ground plane(AiShadowmatte), HDRI dome(Visibility 0)

To generate shadows, add a ground plane, but if you want to exclude the plane from rendering, apply an ‘AiShadowmatte’ shader to show only shadows.

Render setting – Common

Once all the settings are checked for rendering, proceed to render your scene. Start by reviewing the render settings, where you can adjust parameters like image format, color space, metadata, frame range, camera, and image size under the ‘Common’ tab.

Render setting – Arnold Renderer

Additionally, you can fine-tune render quality in the ‘Arnold Renderer’ tab. Autodesk offers a detailed guide for further reference.

Render setting – AOVs

Don’t forget to configure Arbitrary Output Variables (AOVs) if you need multiple channels for post-processing. You can add render paths to the list by clicking arrow button.

  • However, Ambient Occlusion is not on the list, so you have to add it using ‘Add custom’ and set the name of the channel. Afterward, select it on ‘Active AOVs’ list, go to Attribute Editor, check ‘Custom AOV’ option and add an ‘aiAmbientOcclusion’ shader.
  • When merging channels into one file, toggle ‘Merge AOVs’ in the File output options of the Common tab.
Render Sequence

Finally, initiate the rendering process. Switch to the ‘Rendering’ shelf, click Render-Render Sequence, adjust settings such as output location and camera, and press ‘Render Sequence.’ Rendering speed depends on your settings and scene complexity, so be patient.

Rendered AOVs
Applied ZDefocus in Nuke

For a practical test, I rendered robots with multiple channels and imported the exr file into Nuke, including Z-depth for using ‘ZDefocus.’ The result demonstrates the effectiveness of ZDefocus applied through the Z-depth channel.

Now equipped with basic Maya rendering knowledge, I look forward to delving into advanced tools in Maya, such as simulation and detailed animation, in the upcoming term.