Maya FulldomeIBL

Andrew Hazelden edited this page Jun 7, 2017 · 8 revisions

Table of Contents

Introduction

The FulldomeIBL tool creates a custom mentalrayTexture based shading network that lets you feed fulldome 180 degree images and image sequences into mentalray's IBL node angular texture input. The FulldomeIBL tool works with Maya's improved "emit light" IBL lighting system.

Using the FulldomeIBL Tool

To add a FulldomeIBL image to your scene you can use either the Domemaster3D Menu item (found in the Rendering menu set) or the shelf tool.

Shelf Tool Let's start by clicking the FulldomeIBL shelf tool icon.

FulldomeIBL Creation Dialog

The FulldomeIBL creation dialog will appear and ask you if you want to apply a circular alpha mask to your FulldomeIBL imagery. This is useful for hiding content in the border zone of the domemaster frame like textual notes and comments that would otherwise show up in the environment map background.

If you click the "Yes" button, a multiply divide node will be added to the shading network along with a custom mentalrayTexture named domemaster_mask.png.

FulldomeIBL Circular Masked Shading Network

If you click the "No" button a standard FulldomeIBL shading network will be created without the alpha mask texture.

FulldomeIBL Standard Shading Network

After the FulldomeIBL tool finishes, you will have a new mental ray IBL shape in the scene which looks like a large sphere with a yellow wireframe grid. In the outliner this node is called "mentalrayIbl1". You can rotate this shape if you want to align the fulldome environment map texture with objects in your scene. If the mental ray IBL shape is the wrong size, you can scale it up or down to match your scene scale.

FulldomeIBL Standard Shading Network

You can open up the IBL shape in the Attribute Editor using multiple techniques. You could select the IBL shape in either the perspective view or the outliner, or you could open the Render Settings window, switch to the Indirect Lighting tab, and click the Image Based Lighting navigation arrow.

In the Attribute Editor window click on the "mentalrayIblShape1" tab. This will let you change the Render Stats settings for the primary visibility and environmental visibility of the environment map, or adjust the brightness of the environment map for background visibility, or for adjusting the light output of the image based "Final Gather" / "Emit Light" light emission.

FulldomeIBL Standard Shading Network

The IBL shape node typically uses an angular mapping projection that expects a 360° field of view angular image like a Debevec style angular light probe / HDRI image.

The FulldomeIBL tool works by connecting a custom mental ray shading network to the mentalrayIBLshape's texture input and uses a mib_texture_remap node to adjust the framing of a 180° fulldome image to fit inside the expected 360° angular input frame size.

A common issue with the mental ray IBL shape is that the texture can appear reversed so writing and objects in the environment map will backwards. A solution to this problem is to edit the mib_texture_remap node's transform attributes. By typing a -1 value into the first Transform input field we can flip the texture horizontally so the environment map is facing the correct direction.

Flipping the Texture Direction

Default Fulldome Texture Map

A 4K resolution version of Aaron Bradbury's fulldome alignment pattern is used as the default texture on newly created FulldomeIBL environments. This pattern can be useful as a starting point as it provides dome theater screen coordinates that can be used to help with the placement of objects in your scene.

Fulldome Alignment Patterns

The fulldomeAlignmentGrid_4k.png texture map is stored in the following Domemaster3D folder locations:

Windows Image Location:

C:\Program Files\Domemaster3D\sourceimages\fulldomeAlignmentGrid_4k.png

macOS Image Location:

/Applications/Domemaster3D/sourceimages/fulldomeAlignmentGrid_4k.png

Linux Image Location:

/opt/Domemaster3D/sourceimages/fulldomeAlignmentGrid_4k.png

Applying FulldomeIBL Presets

We aren't limited to using just 180° fulldome images in the FulldomeIBL tool. There are several presets that make it easy to load 180°, 220°, 270°, and 360° angular imagery.

Applying a mib_texture_remap Preset

The presets are accessed by clicking on the dome_mib_texture_remap node in the Hypershade and selecting the presets button in the Attribute Editor window. These presets adjust the mentalrayTexture frame positioning and cropping so you can feed in imagery with different angular degree values and still get the correct results in the mentalrayIBL shape node.

Choosing a mib_texture_remap Preset

The angular/fulldome presets are named:

      angular_180_degree_remap
      angular_220_degree_remap
      angular_270_degree_remap
      angular_360_degree_remap

Note: The HemirectIBL tool presets are also listed in the same window since the hemirect image based lighting tool uses the same mib_texture_remap node to prepare the image framing. The main difference between the FulldomeIBL and HemirectIBL tools is that the FulldomeIBL tool applies the imagery to the mentalrayIBLshape node using an angular mapping and the hemirectIBL tool uses a spherical mapping.

Adjusting the Image Brightness

The FulldomeIBL shading network has a remapColor node that can be used to adjust the brightness of the environment map imagery. If the FulldomeIBL texture looks too dark for your tastes, you can use the dome_remapColor node to brighten the texture map up at render time.

dome_remapColor Node

To adjust the overall image exposure, select the dome_remapColor node in the hypershade and expand the remapColor node's Input and Output Ranges section. The Output Max attribute is a direct multiplier for the image brightness. A value of 2.0 will make the image 200% brighter, a value of 4.0 will make the image 400% brighter, and a value of 0.5 will make the image 50% as bright.

There is a set of remapColor presets that can be used to boost the brightness of 8-bit low dynamic range textures like JPEG/PNG/Targa/Tiff/IFF images into the floating point HDR color range. This can really help with image based lighting done using either mental ray final gather or light emission modes. The presets are accessed by clicking on the dome_remapColor node in the Hypershade and selecting the presets button in Attribute Editor window.

Applying remapColor Presets

The remapColor presets are named:

      default_settings
      ldr_to_hdr_boost_05x
      ldr_to_hdr_boost_10x
      ldr_to_hdr_boost_15x
      ldr_to_hdr_boost_20x
      ldr_to_hdr_boost_25x
      ldr_to_hdr_boost_30x

Choosing the Right remapColor Preset

The last part of the preset name, like the _10x part of the ldr_to_hdr_boost_10x preset indicates how many times brighter the highlights will be lifted in the image.

If you have an image that is already an HDRI file you, can use the default_settings mode to reset the color profile curves and then adjust the overall image brightness using only the standard colorRemap node's Output Max attribute.

Navigating the Attribute Editor

Usually a shading network is browsed using the Maya Hypershade or the Node Editor views. This chapter will help you navigate the FulldomeIBL shading network connections using the Attribute Editor.

As a tip, you should start the process by selecting the "mentalrayIblShape1" node in the outliner.

FulldomeIBL With No Masking

FulldomeIBL With No Alpha Mask

Step 1. With the mentalrayIblShape1 node visible in the Attribute Editor, click on the Texture attribute navigation arrow.

Step 2. With the remapColor node visible in the Attribute Editor, click on the Color attribute navigation arrow.

Step 3. With the mib_texture_lookup node visible in the Attribute Editor you have two choices:

If you click on the mib_texture_lookup node tex attribute navigation arrow you will arrive at the mentalrayTexture node which allows you to load a texture map. The mentalrayTexture node has the Extra Attribute based image sequence tools.

If you click on the mib_texture_lookup node coord attribute navigation arrow you will arrive at the mib_texture_remap node which has the texture placement controls that can be used to adjust the "field of view" settings for the FulldomeIBL environment map texture. You can use this node to apply an attribute preset like angular_180_degree_remap or angular_220_degree_remap.

FulldomeIBL With Alpha Masking

FulldomeIBL With An Alpha Mask

Step 1. With the mentalrayIblShape1 node visible in the Attribute Editor, click on the Texture attribute navigation arrow.

Step 2. With the remapColor node visible in the Attribute Editor, click on the Color attribute navigation arrow.

Step 3. With the multiplyDivide node visible in the Attribute Editor, click on the Input 2 attribute navigation arrow.

Note: The multiplyDivide node is used to mask out the fulldome frame boundary labels. Input 1 is used for loading the circular alpha mask texture that crops out writing around the fulldome frame. Input 2 is used to access the regular fulldomeIBL color texture map.

Step 4. With the mib_texture_lookup node visible in the Attribute Editor you have two choices:

If you click on the mib_texture_lookup node tex attribute navigation arrow you will arrive at the mentalrayTexture node which allows you to load a texture map. The mentalrayTexture node has the Extra Attribute based image sequence tools.

If you click on the mib_texture_lookup node coord attribute navigation arrow you will arrive at the mib_texture_remap node which has the texture placement controls that can be used to adjust the "field of view" settings for the FulldomeIBL environment map texture. You can use this node to apply an attribute preset like angular_180_degree_remap or angular_220_degree_remap.

Using Animated Fulldome Texture Maps

Since it's handy to be able to use moving image sequences in the background of your fulldome renderings, I've extended the features available in the mentalrayTexture node so it can handle image sequence based file textures.To do this, the FulldomeIBL tool uses the same "image sequence" add-on expression and Extra Attributes as the "color image sequence" tool in the Domemaster3D shelf.

You can read more about the image sequence feature on the Maya mentalrayTexture Image Sequence Wiki Page. The wiki page includes details on how to set up the Extra Attributes so you can feed in your animated texture maps using one of the following based formats:

  • name (Single Frame)
  • name.ext (Single Frame)
  • name.#.ext
  • name.ext.#
  • name.#
  • name#.ext
  • name_#.ext
  • Native Image Name (Passthrough)

Fulldome mentalrayTexture image sequences

Rendering FulldomeIBL Scenes

The FulldomeIBL image sequence mode requires your render farm software to distribute the rendering job using 1 frame per packet / render slice so a new image is loaded for each frame of the sequence.

For more details on the image sequence mode rendering process check out the Render Farm Software section on the mentalrayTexture Image Sequences wiki page.

Clone this wiki locally
You can’t perform that action at this time.
You signed in with another tab or window. Reload to refresh your session. You signed out in another tab or window. Reload to refresh your session.
Press h to open a hovercard with more details.