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Maya Support Solutions Podcasts

We have 5 new Maya Support Solution podcasts up in the Subscription Center Some people have told us they find our podcasts difficult to find, so I figure I'd lend a hand.

 To view the podcasts, first, you need to log in to the subscription center at http://www.autodesk.com/subscription. Click on the Login to Subscription Center button in the top right of the page.

 

How to install Mental ray custom shaders

Pre Maya 2008, youvneeded to go to the install location of Maya to install custom shaders.

Example : C:\Program Files\Autodesk\Maya8.5\mentalray

Then you needed to modify the maya.rayrc and add both the lib and include files.

Post Maya 2008, there is a much easier way, Go to 

Window > Rendering Editors > mental ray > Shader Manager

Hit he Browse button and locate the custom Shader .dll file (windows) or .so file (MAC)

Add the system time to the render caption, Pt 1

In this post, I show you how to add an extra item to the caption in the Render View.

polygon mesh can't be exported as a subdivision surface

This error usually appears when using mental ray approximation editor in conjunction with a displacement map. Pre Maya 2008, the approximation could not handle N-sided polygons, therefore it it will output this error.

To fix it, go over your model and look for any N-sides and change them to either a Tri or a Quad face. Post Maya 2008 the CCmesh can support N-Sided faces, so you won’t get that error anymore.

However some users still like to disable the CCmesh and rely on the old method, therefore they might be faced with that error again if using a poly mesh with N-sides.

Toggle the visibility of a single Joint transform node.

In response to the post Turn a joint node into a regular geometric object with MEL David Hunt added the following comment:

"I have always wondered if it would be possible (..) to add a boolean attribute to joint transforms that toggles the joint connections on/off for the given joint. Ideally, this would NOT affect any children like visibility typically does. That way we could add shape transforms to some joints but leave joint display visible for others on the same skeleton."

Well David, it is possible, and here is how you toggle the display of a single joint node without affecting the visibility of its children:

1. For a selected Joint, open the AE.

2. Open the Display tab, and find Drawing Overrides.

3. Enable Overrides and set the Level of Detail to Bounding Box.

4. To make the rest of the chain visible again, select the Joint's immediate child(ren) and turn on Drawing Overrides > Enable Overrides.

See what I mean.

If your Joint has a shape node, it will remain visible, as do all of the Joint's children.

Owen

Doing vector math in Maya with python

Eric asked on Ask Autodesk about using Python to do vector math in Maya

 is there a way to get all the vector math methods from mel eg.

vector $v = <<1.0,2.0,3.0>>;

mag $v;

this, cross products, matrix multiplications, etc. How do I do this in python? Can I do this in python; if not, what is the recommended way of doing all this?

Maya's Python does not come with any of the math tools that exist for MEL, so all the docs for the commands abs, angle, bessel, ceil, clamp, constrainValue, cos, cross, crossProduct, , deg_to_rad, delrandstr, dot, dotProduct , equivalent , equivalentTol , erf, exp, floatEq , floor, fmod, gamma, gauss, getLastError, getProcArguments, hermite, hsv_to_rgb, hypot, linstep, log, mag, max, min, noise, normalize , pointMatrixMult , pow, rad_to_deg, rand, randstate, rgb_to_hsv, rot, seed, sign, sin, smoothstep, sphrand, sqrt, tan, trunc, unit will say Only available in MEL

some of them are available from the math module, such as sin and cos, so you can do

import math
math.cos(60.0)
# Result: -0.952412980415 # 

But not the vector functions like cross and dot, so we'll need to get those from somewhere else.

Render passes comes out black

We received this inquiry from a customer , where all of a sudden all the render passes come out black.

This was to due to the fact that the “Use Legacy Maya Base Shaders” was turn On (Off by Default).

Render Settings > Option Tab > Customization

 

Please note that Maya 2009 has a new Shader library that will allow it to extract the passes at render time, Therefore this option must be turned off in order to calculate the passes

Render Proxy (Assembly) and Render Passes

At the moment not all passes will support Render Proxies.
Some of these passes are Coverage , Ambient Occlusion and Camera Depth.
In order to obtain these passes in your assembly file, you can do the following.

1. Open the Maya file that you wish to use as a Render Proxy
2. Add the render passes of choice for example (AO , depth and coverage)
3. Export the file as Render Proxy
4. Create a new Maya file and use the render proxy as you do normally
5. Add the passes of choice (AO – make sure to enable the AO in the Indirect lighting tab- , depth and coverage)
6. Render with mental ray and you will get all passes as above

Print the name of the render camera to the Output Window.

Occasionally, when I render a frame, my heart sinks when I see the first pixels appear in the Render View as I realise that I rendered the wrong camera.

 

I'm going to show you how to print the name of the render camera to the Output Window. And by modifying a Maya start-up script, you can make this a default feature.

Modify a Maya start-up script.

My next few posts involve modifying a Maya start-up script. I realise that not everyone is comfortable doing this, so I wrote this post as a primer to show you how to make alterations safely and without the risk of breaking the original scripts.

That's not to say that there isn't a risk involved in adapting Maya's default scripts; this is not something Autodesk encourages or supports.

But if you really have to modify a Maya start-up script, this is how I would go about it.