Maya Station

Open EXR files are very large when rendered out of Maya

This is because the open EXR don’t have any type of compression on them.
We received multiple requests for adding compression on the EXR files
Autodesk has placed this product issue on development's product modification schedule.

Final gather contribution is lost behind glass objects

For the Final gather contribution behind glass containers, you will need to adjust the MAX Trace Depth
This option is similar to -trace_depth but applies only to finalgather rays.
The defaults are all 0, which prevents final gather rays from spawning sub-rays.
This means that indirect illumination computed by final gathering cannot pass through glass.

Note: This is not compatible with mental ray 3.1 and earlier, which used the trace depth (which defaults to 2 2 4) for final gathering.

Ambient occlusion layer with displacement

When using an  object that has displacement map. and adding it to a Render Layer using the Ambient Occlusion preset, the object lose its displacements.

Simply copy the shading network of your displacement
add an mib_amb_occ texture to the incandescence of the new shader
Adjust the mib_amb_occ as desired
repeat the above step for any other displacement shaders
Connect the same mib_amb_occ to the rest of the shaders

Selection by Reflection

It seems that this feature is somewhat over looked by lots of users.
When modeling a symmetrical object , it makes it much easier to enable this feature

To enable this function
Double click on the selection tool to open it’ attribute editor
Check Reflection

 

Rounding floats to integers

Since there isn't a specific MEL command for rounding floating point numbers to the nearest integer, we have to be a bit clever. Thanks to Julia Pakalns for a particularly elegant solution..

float $float = 3.14159265;

floor ( $float + 0.5 );

// Result: 3

And in Python? Just use the round() function:

float = 3.14159265

round ( float , 3)

# Result: 3.142 #

round ( float )

# Result: 3.0 #

round() is a built-in Python function, so no need to import anything from the math module.

OK, so now what about rounding a float to a given number of decimal places, in MEL ?

Bern asks

"[...] can you please ask for a 'rounding' function instead of having to write something such as:

proc float round(float $val,float $dec){

    $sign = `sign $val`;

    float $dec = `pow 10 $dec`;

    $val = (int) (($val + $sign*5/($dec*10)) * $dec);

    $val = ($val / $dec);

    return $val;

}

...each time i want to round a number"

Well, Bern, one answer would be to use the python round() command, except you invoke it from MEL:

python ("round (100.555, 1)")
// Result: 100.6 //

Although this gets messy when you want to parse a MEL variable.

So my only other suggestion is to incorporate Julia's idea:

global proc float round(float $val,float $dec){

float $dp = `pow 10 $dec`;

$val = $val*$dp;

$val = `floor ($val + 0.5)`;

return ($val/$dp);

}

Save this procedure to a script called round.mel, put this in your user scripts directory and it'll be sourced automatically the next time you launch Maya.

Owen

Optimizing mentalray textures

Command line tools available with maya to create optimized texture format

1.  imf_copy
allows to convert all files supported by mental ray, including optimized file format

2.  imf_disp
allows to display all files supported by mental ray, including optimized file format

Script example to convert all textures files in a given directory
From a Windows DOS command prompt, type

for %i in (*.bmp *.tga *.jpg) do imf_copy -r -p %i %i.map
foo.bmp will be converted to foo.bmp.map

If you put the above command line into a batch file or cmd file, you need to change few things in order to work (DOS)

for %%i in (*.bmp *.tga *.jpg) do imf_copy -r -p %%i %%i.map

Script example to convert all textures files, recursively from a given root directory

cd to_drive_letter_where_the_root_directory_is_located
cd to_root_directory

for /R %i in (*.bmp *.tga *.jpg) do imf_copy -r -p %i %i.map

If you want to remove the original file extension and replace it with .map here is how you proceed:

cd to_drive_letter_where_the_root_directory_is_located
cd to_root_directory

for /R %i in (*.bmp *.tga *.jpg) do imf_copy -r -p %i %~dpni.map

Construct explanation:

1.    %~di provides the drive letter of the file contained in %i

c:

2.    %~pi provides the path of the file contained in %i

\Documents and Settings\My Documents\Maya\Projects\MayaIsSoCool\

3.    %~ni provides the filename of the file contained in %i

RobotDiffuse

4.    %~xi provides the file extension of the file contained in %i

.bmp

Concatenating the construct allows to recompose the entire file path.
%~dpni will result into

c:\Documents and Settings\My Documents\Maya\Projects\MayaIsSoCool\RobotDiffuse

Thanks to Dave Lajoie for his Tip

Focus the AE on a given node

When you select a geometric object the AE loads all the nodes connected to your object into a stacked, tabbed layout, with the Shape node open "on top".

That's neat if you want a shortcut to your Shape node attributes. But if you wanted the object's Transform node "on top" instead, you have to open it yourself.

Here's a way around that...

Semi transparent shadows appear at render time

We receive this question quite often, where a customer reports there is unwanted semi transparent shadow when using a texture file with embedded alpha.

 

This is due to the default value of the Shadow Attenuation , found under the ray trace parameters of your Shader.

Drop the value from 0.5 to 0 and you will get the proper result

 

 

For more information about Shadow Attenuation , please refer to the online Docs.

User Guide > Rendering and Render Setup > Shading > Shading Nodes > Material nodes - Maya software > Surface materials >

Links to Autodesk Technical Solutions is broken

You've probably noticed that the links to the latest Technical Solutions - listed on the left - cannot be resolved.

We are working on fixing this and I'll let you know as soon as they are available again.

In the meantime, please go to the Autodesk Knowledgebase to search for Maya Technical Solutions:

http://usa.autodesk.com/adsk/servlet/ps/index?siteID=123112&id=9262197&linkID=9242258

Thanks for your patience.

Owen

Changes to the weblog

First things first, thanks to all of you who replied to my survey a few weeks back. Happily, the feedback was mostly positive.

All things considered, there will be a couple of minor tweaks to the layout of the blog.

Nothing more than a spring clean. I reshuffled the Categories and deleted the empty ones. I've added links to several self-help pages in an effort to turn the blog into a sort of self-help dashboard. And in that spirit, I'll write more about what it is we spend our time doing here in product support.

Also, we shall do our very best to post on a wider variety of topics. That said, Ash's specialty is mental ray and I'm always looking for ways to make my life easier, so expect more scripting and rigging ideas...

And it's about time I looked into Python a bit more too.

The best suggestion we had was for a user submitted "question of the week". I like this idea and will follow up shortly. While trying to steer Maya users to post their questions where they're likely to receive an answer - the Area, Subscription Centre, Ask Autodesk - I don't see why we can't publicly discuss certain topics through the blog. So if you'd like to raise a question, please send it to me:

• owen.burgess@autodesk.com
  (make the title something nice, like "mayastation question of the week")

Depending on the response, I'll choose questions that are likely to impact a wide range of users - for the benefit of the silent majority, and perhaps even our software developers!

Thanks and keep reading!

Owen