Josh Mossotti

There seems to a growing trend among the humans to annihilate one another on the roads while texting from their mobile phones. My research has not produced a pinpoint time or place where the inception of this ritual began, but it seems to me it would be around the date and place that texting was offered as a feature on mobile devices.

The current anti texting while driving campaign looks to be organized by the same people who have launched a holy war against drinking while driving. The groups have a new outlet to fill medias with grotesque images of the results caused by gitty little girls texting while driving and having a down right good time doing so. In all fairness I stand behind such attempts to engage individuals in the gravity of their decisions, but I still read and watch daily doses of local and national news coverage telling of tragic accidents caused by people drinking up their courage to make their commute home from the bar into an NASCAR race. Their hangover involves a jailhouse breakfast filled with sorrow and remorse followed up with a lifetime of guilt for the family of five they swallowed with their last shot of alcohol as they exited the bar. The punishments never seem to fit the crime.

As you take a step back from the situation you can say those several thousand incidents per year are simply isolated events, but at some point in your argument you will have to draw the conclusion that the foundation of the system is flawed. We know for a fact humans are flawed. We make poor choices all the time. There needs to come a time when we can all look at the situation honestly and understand that people are not able to manage their behavior flawlessly to create a safe and civilized society. In the end the fear tactics campaign fundamentally can never work because it still puts the responsibility back into the hands of the individual to make smart choices. Fool me once, shame on you. Fool me twice, shame on me.

The only way to combat this plague is to take proactive steps to cut off the problem at the choke point. If mobile devices are able to be detected as they enter or approach a vehicle and disable texting capabilities, we will no longer have to trust that people are going to make the right choice this time. I know what you’re thinking. This is too far fetched, I mean whats next, hover boards like in ‘Back to the Future II’? In fact, most bluetooth devices are already able to recognize cell phones when they are in a certain perimeter of a vehicle and can automatically switch your phone to alternate mode when the ignition is on. Of course the second a plan like this would be implemented, some computer savvy rebel will offer work around solutions that bypass normal device functions. If it is made a matter of law however, it will be easier to dismantle the distribution of such applications and will put some responsibility on the device makers and service carriers to monitor and disable the functionality of the applications without having to deal with the current issues of breaking FCC regulations for openness. Since the original direction of this argument was directed at the trend of texting while driving I will keep from delving too far into similar features that detect BAC levels in every single car to prevent drinking while driving. The practice of individuals having the sober friend offering up untainted BAC in order for their drunk friend to start the car needs to be carefully handled.

For these campaigns to truly work we need a collective societal consensus to take action and afford a few minor inconveniences in everyone’s daily routine to combat the problems that create unsafe conditions and tragic results. These minor sacrifices can make a massive impact on driving related casualties and as a society we need to demand that it is worth it.

This post is a little bit different from the normal drivel I provide world wide. As I have mentioned before and in the ‘About’ section I earn my keep as a visual effects artist for film. One of the more interesting aspects of the job is the problem solving that goes into creating desired effects. Sometimes the search for answers to problems I encounter become a project in itself and even good resources can end up using cryptic wording that makes its hard to understand a procedures implementation in production. The long and short of this post will show you how to build occlusion passes using Mental Ray Final Gather that obey transparency maps. I have attached below a downloadable Maya 2008 .ma file in case my walk through does not register, or if you are like me and find it much easier to dissect the scene rather than read someone else’s lecture.

For the purposes of this post I will be referring everything based on Maya 2008.

The current ‘mib_amb_occlusion’ node located in Maya’s ‘hypershade panel’ under the ‘Create mental ray Nodes’ menu, is a great source for delivering an ambient occlusion layer or pass, but to my knowledge does not recognize transparency maps assigned to objects within a Maya scene.

I am going to move rather quickly past that node. If you are here you likely searched for something related to transparencies in ambient occlusions which should leave me to believe you are already comfortable using normal Mental Ray ambient occlusion shaders. If you want more info on that contact me through this post.

In order to run a transparency map into an AO (I’m abbreviating now) shader, we need to use Mental Ray’s Final Gather renderer and a couple of Final Gather specific nodes. In the hypershade panel create a Maya lambert material, a Maya surface shader material and open the both of them in the bottom work area by shift selecting both of them and clicking the ’showUpAndDownstream’ connections button above.

We are now going to grab the necessary final gather nodes from the ‘Create mental ray Nodes’ menu. The first one is the ‘mib_fg_occlusion’ node located in the sub-menu ‘MentalRay Lights’. The second node is the ‘mib_transparency’ node located in the ‘Sample Compositing’ sub-menu.

I am going to generate a transparency map using a Maya based procedural Ramp texture to complete this walk through. You will substitute this for the map you need based on your production. Let’s start by connection the ‘mib_fg_occlusion.outValue’ to the surface shader.outColor by middle mouse click and drag from the ‘mib_fg_occlusion’ node to the surface shader node. This will bring up the connection editor, connect the forementioned attributes to be connected. Connect the surface shader.outColor to the ‘mib_transparency.input’. Connect the ‘transperancyMap.outColor’ to the ‘mib_transparency.transp’. This will automatically connect the ‘transperancyMap.outAlpha’ to the ‘mib_transparency.transpA’. Lastly, connect the ‘mib_transparency.outValue’ to the ‘LambertSG.miMaterialShader’. Be sure when you are connecting that last attribute to be connecting to the shader group of the lambert material. You can now connect the shader to the desired object.

Before all the magic unfolds before your eyes you will need to bring up the attribute editor for the ‘transAO_LambertSG’ shading group. By default there is an attribute ‘Export with Shading Engine’ which is flagged ‘On’. Uncheck this box for the transparency to work. It will not function properly if this attribute is not turned off.

We are almost there and your patience will be rewarded I assure you. We need to turn on Final Gather in the Mental Ray render globals. By turning on Final Gather and ensuring that ‘raytracing’ is turned on this shader now will recognize the transparency maps in and ambient occlusion shader. I would also suggest making sure that your quality presets are set high and adjust the settings in the Final Gather menu to achieve the desired results.

I will close this post by saying that this will likely serve the needs you may have for generating AO passes containing transparency maps. I do prefer the control settings in the ‘mib_amb_occlusion’ node to the ‘mib_fg_occlusion’ but this does the job for now. I hope this helps and is an easy approach to building this shader. You can download the Maya 2008 scene used in this walk through below.

Maya Scene Download

JM Transparent Occlusion Tutorial