Nested References in Maya

I've found myself in the need at work to be able to get all the references a shot had. What you can get with file(q = True, r = True) are only the top level references leaving behind the nested ones.

I've read somewhere that is a good practice trying to avoid such levels of depth, but in this case we were in a closet.

So after a while searching the web and the official Maya python documentation i hit with referenceQuery and the "children" flag.

Finally i developed this simple method that fills a python list with reference filenames:


    def add_nested_references(self,parent_ref_list):
       
        for parent_ref in parent_ref_list:
            child_list = mc.referenceQuery(parent_ref, f = True, ch = True)
            if child_list != None:
                   self.add_nested_references(child_list)
                   parent_ref_list.extend(child_list)

How to Recover Linux Grub Boot Loader

Normally, the order of installation should be first windows then linux so that the grub boot loader is installed and recognizes the windows partition too.

At my job i had to do it the other way around: we had a system with Centos 7 linux and we needed to install Windows to make this machine we useful either to rigging either to production staff.

I inserted the windows dvd and made a new partition in the unallocated space then install.

When i restarted the machine the linux boot loader had disappeared so i was googling how to recover it. Truth is it's pretty simple and after a really few minor mistakes i managed to make it work:

We need first to enter in RESCUE mode with a linux installation dvd/cd.

The system will be most probably mounted in /mnt/sysimage so we make the

chroot /mnt/sysimage

after that we do:

/sbin/grub2-install /dev/sda

to make grub recognize our windows entry just type:

sudo grub2-mkconfig > /dev/null

If everything went well the windows loader entry has been detected, all we need now is to save it to the grub.cfg:

grub2-mkconfig -o /boot/grub2/grub.cfg

Restart and voilà, we have our boot loader back with our windows O.S. entry!!!

Advanced Multithreading GUI Programming with PySide

One of the tasks i was in charge of was to look for a video player in linux that met several requirements from the art director. Some of them were:

- available for linux
- free
- frame by frame backwards and forward playing
- hotkeys for the above, not only buttons
- able to play several clips in a row
- no blank frame between clips
- able to play the audio of the video as well
- autoloop feature
- plays .mov, .mp4, .avi, compatible with the most possible codecs out there.

The autodesk RV Player is the best one according to some experienced animators but we couldn't afford licenceses for each individual.

After testing the obvious ones such as VLC (with jump in time extension), Openshot, MPlayer (with SMPlayer front-end)... All of them were lacking any of the listed features. Concretely i couldnt restrain my disappointment when i found that VLC's extension wasnt working as claimed on the web.

Several days passed by, and in the meantime i was busy doing other stuff and the animators had to deal with openshot which is not properly a video player but rather a video editor.

Anyways i found out that openshot was built upon the media lovin't toolkit video engine (MELT from now on)

So i decided to install it and give it a go.

Couldn't compile the last version 0.9.6 so i tried the 0.9.2 and yeah it worked!!

I was testing it and realized it met all the primary requisites only drawback: it had to be launched from the terminal and this was not as much user-friendly as it should for an animator.

So i was talking to my boss and he suggested coding a gui for maya that listed all the videos in the work directory and launch the player through Maya. That's when i got "hands on".

CODING THE TOOL

I was getting pretty advanced with the gui programming in PySide/Python time to do a test and launch the player came.

And here i discovered a big problem for me that took me some time to resolve. The problem was that the video player was correctly launched if done manually from an opened terminal but when done from the python script with:

import subprocess

command = ["gnome-terminal", "-x", "bash", "-c", "/usr/bin/melt <videofilefortest>"]
subprocess.call(command, shell = False, env = os.environ.copy())

it was giving an error regarding one of the dynamic link libraries (the famous "DLL" files in windows).

TWO WAYS TO SOLVE IT

Further investigation revealed that doing "ldconfig" in that terminal and launching again the player was a solution. "ldconfig" apparently rebuilds a cache file that specifies the name and path of each dynamic library so the system is able to find them. That opened a way to go. I just had to be able to login as root in the script, do a "ldconfig" and then launch MELT.

Another logical way was to mimic the same environment configuration between the two terminals setting and unsetting the ENV variables until both matched. It was clear that both terminals had different configuration. A "printenv > env_good.txt" and "printenv > env_bad.txt" helped to list the ENV variables of both terminals.

SOLUTION

I was jumping from one strategy to the other always testing. Had some difficulties trying to login as root in a script and also i wasn't confortable hardcoding the root password for obvious security reasons.

Finally i noticed that some important ENV variables werent set in the "good terminal" such as PYTHONHOME PYTHONPATH etc. So I decided to UNSET them prior to launching the player. With some help from a linux forum a user suggested also to UNSET not only those variables but also PATH, LD_LIBRARY_PATH. I agreed and finally it worked!!

EXPLANATION

Apparently, the way subprocess.call works is it executes the commands in a child process. Child processes inherit by default the environment from the parent process which in this case is Maya. But Maya itself is launched with specific configuration that doesnt necessarily match the default one.

It was the LD_LIBRARY_PATH what made it work. Makes sense since the concrete problem was the system wasnt finding where the libraries were.


ADVANCED GUI PROGRAMMING

That problem solved the rest was straightforward.

I noticed that the "search-the-filesystem-for-videos" was taking a bit too much time causing the tool to be apparently "frozen". So I decided to add something showing the tool was busy while searching. Something like a "living" waiting pattern.

This obviously led to the use of multithreading: one showing the waiting state while the other performs the search.

First i was wrong because i tried to run in a background process the GUI waiting icon. And i was wrong because a simple search in google showed that all the GUI processing has to be done in the main thread, and not in secondary ones. That is a good thing to know. I just had to switch the tasks and.. voilá.

I was really proud of it, not that it mattered too much since it was more like an aesthetic thing but i have to admit i haven't done much multithreading programming in all my years of programming.

Selection Button In Maya MEL

It's been a while since my last post. The reason is that work's keeping me really busy and i'm learning a lot about Python and MEL. 

The last couple of weeks i 've left temporarily rigging the props and i 've got back to scripting.

It happens that some of the main characters' rigs cannot use FK because the dynamics don't work, so i was talking to one of the lead animators and he came up with an idea, and i was the one to code it and make it possible. I did several scripts that accomplish all the tasks the lead animator asked for the main and secondary characters. Still it has to be tested by the art director and the other lead animators but it feels like it's really useful since it mimics an FK chain with IK controls.

One of the scripts is a panel with selection buttons. Those buttons select each locator so they can animate the locators and then bake the animation.

In MEL we have the "select -r <whatever>" which selects the new by replacing the old. Also we have "select -tgl <whatever>" which adds the selected to the current selection.

The MEL code for a button is:

button -label $label -command $command

Where $command stands for some sort of  "select" as described before. The problem is none of them 

works as it should. I wanted to "select -r" replace but with the ability to Shift Select other locators, this is to add them to the selection if i use Shift just like Maya works.

The solution is to add the following line of code to the $command:

So that finally the button code results like this:

string $command = "string $object=\"object_name_to_select\"; int $mods = `getModifiers`; if (($mods)%2 == 1) select -add $object; else select $object;";

button -label $label -command $command

I'd like to post some rigs i've done but i'm afraid i cannot show the models due to confidentiality terms. 

Shortcut in Linux

How to create a shortcut in linux that executes a shell script

1. We create the shortcut.

Typically it's a ".desktop" ascii file with these entries although it can have more:

[Desktop Entry]
Type=Application
Encoding=UTF-8
Name=Sample Application Name
Comment=A sample application
Exec=application
Icon=application.png
Terminal=false

- The Name specifies the name of the launcher.
- Exec is the most important line as it specifies which script to launch and how it would be launched. We will leave this field blank til we have the shell script written
- Icon we set the path of the app's icon if available.
- Terminal specifies whether the app needs a terminal to run.

2. We create the shell script.

#!/bin/bash

. ~/.bashrc
PATH=$PATH:/srv/XXXX/XXXX/final_directory;
export PATH
cd /srv/projects/myproject

[some commands executing applications]

The first line is a comment indicating which shell will execute the script, in this case BASH.

The second line is a line that loads all the basrc file extensions

Then we perform some tasks such as adding another value to the system environment variable path and export that new entry.

We change our current directory and finally we call some commands that will launch our application.

3. We link the Exec command of the desktop file to the script

Note: if we have successfully coded our script it should work from the command line writing:

sh <ourscriptname>.sh

In our case an example of launching the shell script from our desktop file by double-clicking is

Exec=gnome-terminal -x bash -c "sh /path/to/thescript/scriptname.sh;bash"

Another linux tip: when we try to open a file sometimes we dont get to choose the right program even selecting "open with other programs". The trick to making appear the application in that list is editing as root its corresponding ".desktop" file normally placed in /usr/shared/applications/<name>.desktop and in the "command" or "Exec" field write at the end of the command the following: "<previous_commands><blank space>%U"

We save... and that should do the trick!!!

Job as Rigger/Pipeline TD

After a few frenetic weeks rushing to meet the deadline imposed by the CG Student Awards 2015 (13 May) finally i had something to show. And I say finally because for the last months i've applied for jobs where i was aware i needed at least a demo reel, so instead i used to tell my life in neverending emails hoping to get caught by some samaritan producer.

Well this last week was in the end very productive. I had no more than 3 job opportunities:

- The first one was an internship of a month and a half in Lightbox Entertainment thanks to a master colleague that already works there. You never know how important networking is.

- The second one was an internship at a company in Barcelona but the work could presumably be done from here from Madrid. They told me they really liked my work and that they would put me as rigger in spite of the fact that they were looking for a 3d modeler. They revealed to be very kind: i sure would have loved working for them. The company name is PaperFrog and they are currently making a TV3 show regarding animals and dinosaurs.

- The third one, the one i chose, is at a company in the center of Madrid. They are starting the production of a new feature film but they don't have made many claims regarding this yet. The film is intended to deliver next year and i have a contract for almost the rest of the year. I cannot talk really much about it because of the confidential terms but in the press note they released in April they say Spa Studios has done the character development and that the script has been written by the guy that worked in Madagascar 2 and others. It looks really promising.

I leave you here with the show reel i presented to the CG Student Awards. I very doubt that i win anything but the purpose for me was to do some work and have something to show when applying for a job.

CG STUDENT AWARDS 2015 - Showreel

Juan Cristóbal Quesada Showreel 2015

UV Texturing: A Problem and A Solution

These days there's been a lack of entries in my blog mainly cuz i'm spending my time developing my demo reel and mainly cuz i want to meet the final deadline of the CG Student Awards 2015.

My intention is to present a short cut of say 2 or 3 seconds but caring about all aspects of CG and after, show the breakdown of everything. It will be a pirate shooting a ship cannon, there will be particles, characters, hard surface modeling, compositing and.... texturing!

Yes the problem i faced i want to talk about now is making the uv's of my cannon. I mean, i could just have done automatic uv's with mudbox but i wanted to follow the same process as in videogames and what the hell , i wanted to learn how to make proper UVs!

For this, i had my cannon finished and i exported the base mesh without smoothing/subdividing it to an OBJ file in order to be imported in UVLAYOUT 2.06. The UVs are always made in the low base mesh resolution.

Well, i started working in the uvs, it was a lot of work since i handmade all the uvs of even the tiny nails. And when i got to the point where i wanted to export my model with the uvs if found what i thought was a big problem: Headus UVLayout 2.06 exported all in a single mesh, despite the fact that it can read and load an obj with groups of meshes.

So what a problem i thought, since i wanted to be able to maintain the groups of meshes to work easily when texture painting and giving highest resolutions to different parts of the cannon. I really though at first i had wasted a lot of time.

The first thing to clarify was if the problem was effectively from the Headus UVlayout 2.06 tool. Navigating through the forums of UVLayout i found exactly that from version 2.07 up until the current they added the functionality to export an obj with several groups of meshes!!. Well from now on i will work with Headus  UVLayout 2.08 if i can.

Now the problem was still there: how to transfer the uvs from the obj with single mesh to a multimesh object with no uvs.

The answer again was in the internet. In Maya there is a tool called "Transfer Attributes" which can do just that: it transfers the properties of a mesh to another, i was still a bit skeptical since one obj file was all packed in a single mesh and my Maya cannon original low res file was grouped into different meshes, so not quite sure it would work.

I opened my Maya file with the low res grouped into meshes ship cannon and i imported the obj file with the UVs. Selected both, did "Transfer Attributes" Options, checked "UV" and applied..... And it Worked!!

Now I have at last, my model separated and grouped in different meshes all with the same UVs i had worked!!!. Now I can proceed to Mudbox and start painting!!!