Doctoring Soft body transformations in Nuke -- Part I -- Combination of ST Map and keen tools

 

Hey Guys, 

So today we are here to witness on how to harness the full potential of engineering the transformations in nuke using several techniques. 

I was thinking about this quote,

 " The purest form of pleasure is none other than having mind control and being discipline"

told by a wise man.

Today, I am here to talk about ST maps, As we know basically, ST maps have various uses for it own. but, some of it manipulates the transformations, for our comp basically.

 For going in deep into this everyone knows what and normal map is.  Not information in black and white data from ranging 0 to 1 which creates bumps and displacement within the 3D surface.   Exactly like that ST map takes the uv coordinates and uses the map to doctor the transformation happening.  lets see Some applications regarding that.

The first one  we are about to see this tuckins like fat, clothes and beauty fix.  This is one of the application that every compositor are there should know to increase their efficiency of compositing.

First of all what's happening is we are creating  a custom St map to manipulate our transformation.  In here we use the expression node to create a custom St map.

Now ask we work on our ST map or our expression node it affects the transformations in our input.

The normal transformations couldn't create the blend a soft transformation that we need.  Basically what you are doing here is converting our RGB data into a map that helps us to transform anything.  We could even add a track to continue the motion. 

Here we come to next main application in which St maps have been extremely useful.  So let's take an example of a shot.  

As everyone know there are lot of shots where we should recreate body parts , or comping a body part from another shot, or like a robotic arm or something. But there will be certain problems in those cases. 

For example, If we take this shot, the women is sleeping, As we know, there ll be a basic breathing movement, to match. Well, we can take a track and comp it. But as we progress we begin to notice that the breathing moments will be different in each places. 

Body will have a larger breathing movement whereas, those shoulders will have a reduced movement which reduces slowly down to the hands (hands will mostly static)

So the common solution we go for is just masking and giving a separate track. But that don't go well, in human bodies and soft bodies. But, ST maps will come handy in soft body transformations.

So we have got to use separate tracks for seperate pieces of body. Here we can just use the ST maps and manipulate seperate parts of the body using seperate movements but with blending of rgb data without blurness. 

I know that most of the compositors out there use these techniques and its pretty common but, I personally think there are more to it. We can use these for many things such as set extensions, advanced comp works and peculiar paint situations. Thus ST maps are pretty underrated.

So, lets talk about keen tools. I know its a whole another topic. But I just want everyone to have glimpse at this blog, whereas there are hard situations, in keen tools where the edges doesnt blend. I know many wouldn't've have tried this. We have a particular way to use ST maps play a pivotal role in maximising the use of keen tools. 3d projections like keen tools.

Here we go, about keen tools. there are multiple basic tools like face builder, face tracker, geo tracker and stuff.

to give an outliner, keen tools is a plug in where it enables you to create a face geometry and allows you to match - move the face of our plate inside nuke. ofcourse, It is doing a remarkable job and a very useful tool.  

first of all, We build a 3d model and configure the mesh according to the face in the input. whereas in that part keen tools have done a remarkable job. Then what the plug in does is track the face exactly using the techniques of mocha pro's power mesh. And my focus is not just explaining the tools, I just want to convey how I used tools to maximise its use in comp industry. Well Well, Then we would unwrap the texture, work on it, and wrap it again which gives us a good workflow. For example, I worked on a shot where, we need to comp a face with multiple marks and stuff on a characters shot. Well. keens tools played a significant role in that. So after the uv is unwrapped, we can just play with it like a 2d image, Now we can use soft body transformations using ST maps we saw above, which would be give us a great advantage in shots such as, face comping situations like a deformed face or a an addition of a robotic structure to a face, stuff like that. This blog isnt particularly for keen tools, Its for soft body transformations. Whereas, the tiny little bumps are created by ST maps with the help of transform instances so that it will be helpful. ST maps can be used in transformations within Keen tools and other projection systems.

So the thing about displacement in keen tools, we don't displace the face model directly. We displace the RGB data using St maps whereas it gives a displaced look when passing through the workflow. Here I have used a noise as mask for ST maps, and you are free to explore.

-- Well another thing about ST maps is how we use them in 3d workspace. This is more about how we take ST maps to the next level.

Lets take a situation, where we need to do some color corrections at the last minute or add some images or patches to nuke projection systems. Well we dont have time to rerender nuke 3d systems, where we couldnt deal with it. Well this can be used in other 3d software's renders too. Try projecting a UVMap into the 3D system where you ll get a projected 3d system of ST maps, where you can use these to get a great product. 

        

Lets see if plug in a ST map node, where source to to your final RGB output, and your ST map as the projected out. Which will finally gives us the deep compositing feel to our comp. I dont know there may be a better or promising way to do this, But this is the way i found out and I follow. It helps in many conditions and proved to be useful for roto masks to be used in 3d systems.

So we have finally covered, 

-- ST maps and soft body movements

-- ST maps with Keen tools

-- Manipulation of 3d systems with Alpha using ST maps

    

Well see you again on the next blog.

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