When the Mental Ray Installer fails…

Hi all,

we got several reports that the installation of the Mental Ray products on Windows systems may fail, or may not start at all. It turns out, that this happens when the latest NVIDIA drivers (version >390) have just been installed before the plugin.

The reason is: the NVIDIA installer framework keeps some files on the system, in order to speed up subsequent installations, and to retain a history. The latest installer version coming with the most recent drivers is not compatible with the older Mental Ray installer version, unfortunately. We are working on a fix. For a quick workaround, please visit our forum post Mental Ray Installation Fails.

Sorry for the inconvenience, and Thank You for your patience.

Steffen

mental ray for Maya 2016 SP2

mental ray for Maya 2016 SP2 is now available for download here or it is automatically installed by the Autodesk Application Manager.
It ships with mental ray 3.13.1.9 which contains improvements for the BSP2 acceleration structure in certain cases, bug fixes for multi-host rendering and for some framebuffer handling issues. The release notes provide more details.

Several bugs were fixed in the mental ray for Maya translator, notably concerning undo when modifying simple mila_material parameters, satellite rendering issues, and a workflow improvement with regard to the new Create->Lights menu and Environment lights.

Troubleshooting mental ray renders of Maya XGen

Got a nice XGen groom? Everything looks decent in VP2, but in your mental ray renders parts of the hair are missing or, even worse, the hair is not rendered at all?
Don’t panic, these issues can be addressed.

Hair geometry shader setup

In mental ray, XGen hair and other procedurals like cards or randomly instanced archives are handled by a geometry shader. This geometry shader needs to be set up correctly. Usually, this is done automatically by Maya when a new XGen description is being created. In some cases it can happen though, that the geometry shader gets lost or has not been applied. As a result, the XGen primitives are not rendered. To reapply the shader, open the preview/output tab of the XGen window and click the “Setup” button to the right of  “Setup Geo Shaders” in the output settings section:

xgen-setup-geo
After that, your XGen description should render.

Adjusting render output settings

In case your hair looks clipped or thinned-out in a rendering, pay attention to the render output settings. One important setting that usually needs to be adjusted manually is the area, that is supposed to contain all generated XGen primitives. By default, this area is computed from the the bounding box of the XGen base mesh,  plus a padding value of 1 for the XGen primitives.  This padding value is suitable for fitting a default XGen description with hair of length 1. Real-world grooms rarely meet this condition, that’s why renders come out with clipped hair.

To change the padding, open the preview/output tab of the XGen window and click the “Auto Set” button beneath “Primitive Bound” in the output settings section to compute a proper padding-value:

xgen-primitive-bound

This ensures that all hair (or whatever primitives you are working with) is being rendered correctly.
As you groom along, the padding value might need to be re-adjusted, again.

In case the hair appears less dense in the rendering than in the viewport, make sure the “Percent” slider has been set to 100:

xgen-percentage

A lower value will cause the number of generated primitives to be reduced accordingly. This slider can be a nice tool to get fast preview renders with fewer primitives.

Batch rendering XGen primitives

For batch rendering, one additional step is necessary. The XGen collections used in your scene need to be exported to disk to ensure that mental ray can find them. To do so, click on File -> Export Patches for Batch Render in the XGen window:

xgen-batch

Happy hair rendering,
Sandra

mental ray for 3ds Max 2015 SP2

mental ray for 3ds Max 2015 SP2 has been released several weeks ago.

It ships with mental ray version 3.12.1.17.

Several issues were fixed as far as mental ray is concerned:

  • mental ray hang when rendering an empty scene
  • precision problem when using Arch & Design related to computation of glossy samples
  • subset pixel rendering not showing up in rendered frame window when using mental ray

The new NVIDIA GPU Maxwell architecture is not yet supported, but we plan to release a patch very soon. Stay tuned!

 

Inside mental ray

Rendering Imagination Visible