Maya Station

Thanks, Michiel!

As you may have already noticed, Michiel has removed his profile and is no longer posting on the Mayastation blog. In actual fact, he's no longer Maya Technical Lead.

I write this in recognition of his unflinching commitment as Maya Technical Lead to making sure that the 'voice of the customer' remains a keystone in the development cycle of Maya.

Michiel has left us a lot to build on. We will continue to update the blog diligently, share what we know, and deliver the outstanding levels of support that our Gold Support customers have come to expect.

If you want to contact me directly about the blog, feel free: owen.burgess@autodesk.com

Michiel has his own blog here.

Regards,

Owen

Memory management with mental ray - Part 2

32bit and 64 bit OS
When it comes to memory, There are 2 different types of operating systems , 32 bit  and 64 bit.
64 bit has a the ability to reach more memory  on the system over the 32.
Note: 32 OS bit (including MAC) will only reach about 1.8 - 2 GB of RAM , even if you have more than that installed on your machine.

Adjusting the OS Virtual memory
Virtual Memory can be far larger the actual physical memory installed on the machine. The benefit is that it gives the software the impression that there is more memory than it was actually built in the computer.
This type of memory requires that the memory be swapped into disk in order to restart later. It can be somewhat time consuming.

As soon as you go beyond the actual physical memory that is installed on the machine, you will get some sort of performance drop, but the benefit would be you actually finish the render and doesn’t fail on you.
General rule of thumb, use double the amount of physical memory as your virtual memory.

Memory limit settings
If it’s not defined in the scene, mental ray will fall back on a built in memory that is somewhat high, in some cases the memory is not able to fulfill this memory limit request and it will die with memory error.
It is very critical that it’s set to reasonable value, so it will have enough memory on top of that limit available for the operating system. This will be very useful in the case of tight memory situation where mental ray can have some room to operate on.

TIF files and mental ray

In some occasions while rendering with mental ray you will be faced with this error

// Error: (Mayatomr.Output) : file error: C:/Texturefile.tif //

Depending on how the file was created for this error to appear in your render log.

Scenario 1:

Using LZW as a the type of TIF compression is not supported by mental ray

Solution :

Re-save the TIF file without the LZW compression.

Scenario 2:

The TIF file was created on a MAC, then used to render on a PC

Solution:

Re-save the TIF on the PC or use a different file format such as TGA or EXR.

Colors are washed out with mental ray sun/sky

When using het sun/Sky system in mental ray, it adds a mia_exposure  node to the camera.
By default the "Gamma" Value is 2.2, thus the change of color values of your render.
This can be fixed by using one of these two approaches depending on the scene.

1. Per file texture 
   Add a Gamma correct node between the texture and the Shader
   Change the Gamma value to (1 / 2.2 )= 0.455
2. Per Scene
   In the render settings, under the “Quality” tab > framebuffer section change the value to .455
   Under the mia_exposure node, change the Gamma value to 1.0

Trouble Shooting Maya Mudbox Workflow (Part 2)

One of the most common errors in Mudbox - Maya workflow, is the Vertex ID mismatch. In this short tutorial we will explore why it happened and most importantly how to avoid them.

Link

Trouble Shooting Maya Mudbox Workflow (Part 1)

In this tutorial we will explore some of the most common mistakes made while working on the Mudbox-Maya pipeline.

Link

FBX 2010 plug-in is available for download

You can download the FBX 2010 plug-in for Maya (and 3ds Max) here:

http://usa.autodesk.com/adsk/servlet/index?siteID=123112&id=10775855

There is one notable fix, which retains the transform node name for the shape node. Previously, when an object was imported, the shape node did not get the same name as the transform, but was called simply: polySurfaceShape#.

With the FBX 2010 plug-in, the shape node name is as follows : 

transform node name + "Shape"

Thanks,

Owen

Why is my MR material swatch black?

So you're wondering why you can't see the swatch, eh?

You could be forgiven for assuming that you've discovered a bug in Mental Ray for Maya.

That's exactly what I thought too....

I'll give you the answer in just a second, but I invite you to spend a couple of moments thinking about where you would look first..

Create simple collisions without dynamics (or MEL)

A simple rigid-body relationship between two or more objects can be achieved without using Maya's dynamics engine.

In this example, the cam and the plane are connected by a couple of constraints. It's almost as accurate as a dynamic simulation but much faster to tweak.

Best of all, the simulation updates interactively as you scrub the time-line.

Displacement change after scaling an object

This is a common question, with few possible workarounds .
Our starting point , is a simple sphere with a displacement map file.

Once the sphere gets scaled (for this example we will choose a value of 10),  the displacement value will change as well.

The fix would be one of the following

A- File Node approach
In the file node adjust the “Alpha Gain” to match the same "Object Scale" value
you can also automate this by creating a simple expression as follow
file1.alphaGain = pSphere1.scaleX;
Where file1 is the name of your file node, and assuming you scaled the object uniformly therefore scale X = Scale Y = Scale Z

B- Mental ray custom Shader approach
Disconnect the displacement file from the SG node itself
Under the mental ray section in  the SG node > click on the Displacement Shader
Choose mib_texture_lookup21 node > Click on the Tex and navigate to your displacement file
In the mib_texture_lookup21 place a value of 1 for “Factor”
now the displacement values will not change regardless of the object scale