New version of Alembic import shader

Here’s a new version of the abcimport shader that is compatible with mental ray 3.12 and mental ray for Maya 2015. It can be downloaded from this link. The package contains a version for Windows, Linux and Mac OS X, as well as the .mi file with the new shader declaration.

The new features:

  • Support for hair import
    Alembic curve objects are translated into mental ray hair geometry. The curves can be defined with linear segments, quadratic bezier and cubic b-spline (either uniform or with given knot vector). Hair approximation quality can be set with the shader parameter “subdivisions”  (default 0). The parameter controls the number of subdivisions for hair segments. The picture shows a rendering of an Alembic file generated by Ornatrix 3, with linear hair segments and using the shader “mib_illum_hair_x”.hair from abcimport                                                                         Hair alembic file courtesy Ephere Inc
  • Faceset material support
    In Maya, the facesets are assigned with material names. Our abcimport shader now uses this information to reference materials with these names. Facesets can be either triangle or polygon mesh. (Facesets for subdivision surfaces will be added later.) Faceset translation is enabled by default and can be turned off by setting the shader parameter “facesetmaterials” to off.
  • User data support
    Triangle meshes now can reference user data such as color3, color4, point, normal, float, integer. The user data must be attached as “arbitrary geometry parameter property” to objects in the abc file. Please, contact us for more details.
  • Subdivision control for hair, NURBS and subdivision surfaces
    The “subdivision” parameter is now also applied to hair, NURBS trim curves, NURBS, and subdivision surfaces.
  • Motion blur issues fixed
    Motion blur for topology changing abc files is now possible. We fixed an issue with the velocities in Alembic which were not interpreted correctly.

These features will be incorporated into the upcoming versions of mental ray this year.

mental ray for Maya 2015 SP4

mental ray for Maya 2015 SP4 is now available for download. It ships with mental ray version 3.12.1.18.


These are the most important fixes:

  • We are glad to announce that we were able to remove the cause for freezes and crashes on Mac OS X version 10.9, “Mavericks”.   To our Mac OS X users, test it out and let us know your experiences.
  • Some problems around motion blur of XGen geometry were fixed. Please, note that we still recommend setting the Motion Steps parameter to 1 when using XGen hair with motion blur (see mental ray Motion Blur Settings in the XGen Preview/Output window) . This issue will be fixed in the future.XGenMotionSteps
  • Artifacts with texture caching of Tiff textures as well as a problem with imf_copy and multiple level support were fixed.

Check out the Maya 2015 SP4 release notes inside the download for the complete list of fixes and the complete mental ray documentation

Thanks for your feedback.

mental ray for Maya 2015 SP3

mental ray for Maya 2015 SP3 is now available for download here.

This service pack ships with mental ray 3.12.1.17


The most important fixes are:

  • Progressive rendering in the IPR is more responsive now, especially when finalgather is off.
  • Refractions and reflections are enabled for maya_volumefog.
  • Deforming animation in Alembic files imported using GPU Cache is fixed for batch rendering.
  • Fixes in the mental ray core:
    • Unified sampling: fixed possible crash if coverage framebuffer was used in combination with unified sampling.
    • Light importance sampling: reduction of noise artifacts when using point lights with non-physical falloff.
    • Stabilize flushing mechanism for rendering very large scenes.
  • Shader fixes:
    • For layering material shaders (MILA), added support for back_scatter LPE pass.

Check out the Maya 2015 SP3 release notes inside the download for the complete list of fixes.

Complete mental ray documentation can be found here.

BTW, some of these problems were reported here and on the beta forum. Thanks for your feedback!

mental ray’s GPU accelerated GI engine prototype

Autodesk 3ds Max 2015 and Autodesk Maya 2015 ship with mental ray 3.12 which includes a prototype of our new global illumination engine accelerated by the GPU.  We encourage our 3ds Max and Maya users to try it out. Your feedback will help us in making this a big step forward into the future of rendering with mental ray. While the current version is in prototype status and not yet feature complete, we are constantly improving the algorithms and adding new features. Your input is most welcome in this process.

The key idea of the new GI engine is full and exact simulation of the lighting interactions in a scene. This way, we overcome drawbacks from caching techniques and interpolation, and make mental ray more interactive and predictable. The brute-force raytracing approach is accelerated on CUDA capable NVIDIA GPUs making it particularly attractive in this set-up. Its result gets combined seamlessly and automatically with the primary rendering done on the CPU. This ensures full compatibility with existing custom shaders, which do not need to be touched in order to take benefit of the new GI engine.

The following Maya scene is rendered using the new GPU GI prototype in 11 min 34 sec (2 x Quad-core Xeon E5620 @ 2.4 GHz in hyper-threading, 8 GB RAM, Quadro K5000)

Mosque - mental ray 3.12 GI GPU diffuse

                                                                                            Autodesk Maya scene courtesy Lee Anderson, environment from openfootage

 

For comparison, this image is rendered with the classical finalgather automatic mode in 20 min 52 sec (2 x Quad-core Xeon E5620 @ 2.4 GHz in hyper-threading, 8 GB RAM, Quadro K5000)

mosque_fg_auto

 

In the current version, the GI GPU mode considers diffuse-diffuse bounces only, similar to what final gathering typically computes.  In fact, if this mode is enabled without setting further parameters then finalgather settings are used to derive reasonable default  parameters to render towards the same quality. If certain prominent ray tracing effects like mirror reflections or transparent  windows are not used in a scene then the fastest diffuse mode is best suited. For current limitations, see below.

 

The following image is rendered with the GI prototype in diffuse mode in 37 minutes (Core i7-3930K (6 cores), 16 GB RAM, Quadro K5000)

Medieval - mental ray 3.12 GI GPU diffuse

                                                                                                                                             Autodesk 3dsMax scene courtesy David Ferreira

 

The following 3dsMax scene is rendered on the CPU with finalgather force in 13 hours (Core i7-3930K (6 cores), 16 GB RAM, Quadro K5000)

Medieval - mental ray 3.12 CPU

 

The GI GPU mode can be enabled and controlled with scene options or on the command line of the standalone mental ray. We also provide scripts for Maya and 3dsMax that provide a simple GUI for enabling GI GPU (see screenshot). Please, note, that this is by no means how we envision it to be integrated in the applications. It’s rather to provide easy access to users that would like to test the prototype.

 

max-screenshot

Script Download

The scripts to easily enable and access the GI GPU prototype can be downloaded directly from us here:

 

Current limitations

GI GPU transfers the scene geometry, presampled shader data, and some constant amount of buffer memory onto the GPU. Textures are not needed on the GPU. In the case that the GPU memory is not sufficient, there is an equivalent CPU mode. The new GI engine can still be used but the GPU acceleration must be disabled (uncheck the ‘Use GPU’ checkbox). There is also an absolute limit of 25 million triangles.

For GI GPU to be effective, finalgather must be turned on. Some features are not yet supported: distorting lens shaders, motion blur, particles, volume shaders, camera clipping planes, progressive rendering. There is only limited support for scattering shaders, emissive materials, and hair rendering.

Before testing GI GPU, we recommend to install a recent version of the NVIDIA graphic card driver.

 

Feedback and discussion

We would like to hear your feedback and see your renderings using this prototype.  Please join our NVIDIA Advanced Rendering forum, if you have not already, and send us your comments and discuss the mental ray GI GPU prototype.  The dedicated mental ray GI GPU Prototype forum topic here

mental ray for Maya 2015 SP2

mentalray for Maya 2015 SP2 is now available and provides important fixes around XGen hair rendering, layering shaders, massive assembly scenes, native IBL and more. Here’s a short list of fixes that come with the new mental ray 3.12.1.16 and the new version of the mental ray plugin.
Please, consult the mental ray and the Maya 2015 SP1 and SP2 release notes for the complete list.

  • XGen
    The performance of the XGen hair shader has been significantly improved for scenes with dense hair.
  • Layering shaders (Mila)
    Several fixes in the shaders and the UI – namely, possible crash with subsurface scattering initialization, possible NaN values and a too bright contribution of the user IBL environment shader in glossy components, reordering layers with bump or weight connection.
  • Binary Maya file compatibility with Maya 2014 restored
    Some mental ray shader nodes saved in .mb files were not compatible between 2014 and 2015. This is now fixed.
  • GI GPU
    Improved performance of the GPU and multi-CPU rendering, and added support for NVIDIA Maxwell GPUs.
  • Large scene with assemblies
    Fixed possible crash when rendering large scenes with multiple assemblies exceeding physical memory.
  • Native environment lighting
    IPR now automatically updates when changing the new “emit light” features which control the native environment lighting. Fixed brightness difference in IPR versus Render Current Frame.

Happy rendering,

Julia