Photoshop - Workflow

Owned by Systems Next Limit (Unlicensed)
Last updated: 15 Apr, 2021 by Next Limit
3 min read

Photoshop helps you set scenes, advance narratives, and reveal truths with a rich set of pens, brushes, and color and painting capabilities.

The goal of this plug-in is to improve the connection between Maxwell Render and Photoshop. The Maxwell Render Image format (MXI) is a very rich container that can include all channels/passes that Maxwell Render generates, so you can access all of them as layers in Photoshop, avoiding the use of intermediate formats (EXRs and so on).

The Maxwell Render importer plug-in allows you to load MXI files into a Photoshop document. You can choose the bit depth (8, 16 and 32 bits) of the buffers when you load an MXI image. The buffers are shown in separated layers, including:

  • Render buffer: a flattened version of the render, including the contribution of all the emitters together as they got adjusted when the render was finished. For reference purposes. It also details the Sampling Level reached when that render was stored.

  • Light buffers: if the render has been launched with the MultiLight feature enabled, then each individual emitter will be imported in Photoshop as an independent layer, to allow further adjustments.

  • Shadow buffers: if the render has been launched with the MultiLight feature enabled, and the shadow channel activated, each individual light will have an independent shadow buffer.

  • Extra buffers: if the render includes extra buffers, which you have to enable when you launch the render, they will be imported as individual layers. The render buffers include Alpha, Z-buffer, Object Id, Material Id, Fresnel, Roughness, Motion Vector, Normals, Position, UV and Custom Alpha.

Mac OSX version doesn't allow to choose the bit depth. By default, the MXI will be opened in 32 bits.

Please copy alpha into a separate greyscale buffer (create a new document) if you're going to use it as a layer mask. Otherwise, the mask won't look correct with RGB alpha. 

The plug-in creates a layered structure (see the image below), with the extra buffers below (they appear disabled as they do not contribute directly to the final result), and the “light buffers” above them (including the emitters and environment layers). A “Background” layer is also created with a “Background Mask” that allows you to replace the background with a new one of your choice.

All the light layers should be set to Linear Dodge (Add) blending mode (MXI bit depth = 32), and the Background Mask to Multiply blending mode. This way, the whole render will be displayed as the sum of the contribution of all the independent emitters together, giving you precise control over each of them. A render layer, which comes directly from the rendering process, is put on top.

  

Notes

  • The plug-in is unable to save the changes in the original .mxi or in a new .mxi, for the moment. If the users want to save any changes, that must be done as PSD or another layered file format.

  • If you would like to emulate the Maxwell Render Multilight feature, you should blend the light layers using the Linear Dodge (Add) blending mode.

  • The exposure of each layer can be controlled by applying an adjustment Exposure layer, mimicking the ISO/ Shutter slider. To adjust the color of a layer (mimicking the MultiLight color adjustment), you can apply a Hue/Saturation adjustment layer to the desired layer.

  • To avoid the adjustment layer affecting the layers underneath, you should create a Clipping Mask (Alt + Ctrl + G) to ensure the adjustment only affects the desired layer. (See the Maxwell Render Action for Photoshop included in the plug-in package).

  • If you would like to use your own background, you can use the Background Mask layer in Multiply blending mode. Just paste your own background into the Background layer.

  • The MXI must have been rendered with the alpha channel enabled to get this Background Mask information.

  • Due to the Multishadow feature, regular shadow buffers in old MXIs will be shown incorrectly.

  • If you need a shadow buffer of an old MXI you must downgrade the plug-in to the 2.0.3 version.

  • The 64 bits version of the Mac OSX plug-in loads the MXIs with bit depth 32 by default.

  • The Motion Vector buffer appears clipped by its own motion vector alpha information, which is different from the global Alpha buffer.