#Download mental ray for maya 2016 sp4 windows#

We get the green from the light sampling, where thereРІР‚в„ўs no rays. In this case, we get the facing ratio of the polygon normals and the reflection ray. The reflection rays hit the bottom of the torus, go through the facing-ratio ramp, and return red because most of the polygons are facing down towards the plane.

LetРІР‚в„ўs take a look at whatРІР‚в„ўs happening in the different AOVs. The first few lines of the meshLightMaterial shader look like this: if (sg->Rt & (AI_RAY_DIFFUSE | AI_RAY_GLOSSY | AI_RAY_SHADOW)) The meshLightMaterial shader doesnРІР‚в„ўt handle diffuse, glossy, or shadow rays. A mesh light gets a meshLightMaterial shader, which MtoA assigns to the mesh light color (and to the torus shape) when MtoA translates the scene to Arnold. The answer is that there are no diffuse or glossy rays in this situation. The question here is: why do we see red in the reflection AOV, but green only in the diffuse and specular AOVs? Why does the facing-ratio ramp return red for reflection rays, but green for diffuse and glossy rays? The plane below the light has a combination of diffuse, specular, and reflection (Kd=0.7, Ks=0.5, Kr=0.2). The mesh light color is facing-ratio ramp, so that in the Beauty AOV, the polygons facing the incoming camera ray are red, and polygons facing away are green. In this case, we have a torus as a mesh light. Previously this option only existed in Windows. It defaults toР’В lowest, which is lower than the system default that was previously being used. Adjustable thread priority in OS X: OS X now allows for options.thread_priorityР’В to adjust the priority of the render threads.By default is set to auto, meaning that if the number of threads is more than half the number of logical cores on the machine, arnold will pin the threads.

This can improve scalability in modern machines multiple processors.

#Download mental ray for maya 2016 sp4 windows#

(#2733)Р”Р„rnold can pin threads on linux and Windows so they donРІР‚в„ўt jump between multiple processors. Note that, if client code, for instance a custom shader, spawns their own threads manually (with pthread_create or similar), these threads will inherit the same thread affinity, which totally breaks the point of spawning threads in these situations they can either set options.pin_threads to off or they can create their threads with the Arnold API AiThreadCreate() which will un-pin the created thread. This can also be manually set to always on or off by setting the new global option options.pin_threads to on, off, or auto.

The default setting is auto where thread pinning is only enabled if more than half the logical cores are being used. This can improve scalability in modern machines with 16 or 24+ threads and, in the case of ray acceleration structure builds, it can occasionally result in as much as a 3x speedup when all the cores are being used (which is the default in Arnold, options.threads = 0 or -t 0 in kick).

Thread affinity was added in Arnold 4.0.8.0.Р”Р‡rom the Arnold release notes:Threads can now be pinned to cores on Linux.

As of Arnold 4.2.3.0, options.pin_threads works on Windows too.

This way, you wouldnРІР‚в„ўt need to set the affinity at all. For example, you could limit Arnold to six threads, and limiting the threads is probably a better approach, since you wonРІР‚в„ўt end up with multiple render threads running on the same core, which can be bad for performance. If you really must set affinity yourself, you can use the Override User Options to set options.pin_threads to off.Р”В«UTР’В you can also limit the number of threads Arnold uses: in the Render Settings, System tab, clear the Autodetect Threads check box and then set the number of threads. Instead of setting the core affinity yourself, you should let Arnold do it.Р’В By default, Arnold pins threads (sets the affinity) if you use more than half the cores on the machine.