The Process of a VFX Shot

Continuing from the previous blog post on VFX and its uses, this article will discuss how I used VFX to track a sink hole onto the side of the road, with fire and impacts surrounding.

The Process: –

We were given assets by Jon Holmes, one included was a sink hole with an alpha channel, helping to feather the edges of the sink hole into the road, giving it a smooth finish. This was important otherwise the edges would be too sharp; by feathering it help convince the viewer that the sink-hole is indeed there and tracked onto the surface of the road.

SinkHole_Alpha

We used the same process as in the last blog post to track the sinkhole onto the road, however there was a slight twist. With the grid that was tracked onto the cardboard box it was all flat and there was no depth within in the graphic or box – so it was necassary to leave it flat. However due to a sink hole having depth due to it going into the ground we need to cut out the middle of the image which should appear lower down than surface; once put into 3D space its easy to scale up, shift down and backwards in space along the Z axis to help achieve a parallax effect.

The laws of parallax tell us that objects further away from us move slower than objects closer to us – this graphic is a clear example of this. The insides of the hole need to move slower than the surface of the hole. Once cut out and tracked, smoke and fire is added to help create that immersion within that univerise. Because what sinkhole is not complete without fire and smoke?!

Level 2 ::: Workshop 2 ::: Simple Matchmove in AE from The Curious Engine on Vimeo.

Tracking Surfaces in 3D Space with a Moving Camera

The next task was to track 4 points on top of the cardboard box, allowing us to create text and place objects within 3D space while we move the camera around, previously the box moved and the camera was fixed. By tracking the edges of the box using match move it allows the camera to move around to the point where certain track points are off camera – helping create the illusion of objects moving off camera and then reappearing in the same place; helping convince viewers that the objects really are there.

In the following video you can see this clearly; take notice of the magazine in the left lower hand corner side, this surface has also been tracked allowing us to change that graphic should we wish to.

Matchmove ::: AE ::: VFX ::: Basics ::: Example Render from The Curious Engine on Vimeo.

 

Applications in Convergence Task: –

I feel that VFX will be heavily used within my one minute wonder due to it being relevant to what I am interested in, while also being a way to execute these ideas within a film medium. A few ideas I have include tracking my name onto a surface such as a desk or the side of a building or road. I would also use the tracking tools to replace billboards for instance with graphics that I’ve created that could represent thoughts in my head. This for instance could change when I walk past the billboard or if something was said in the narration.

Visual Effects Vs. Special Effects

Visual Effects Vs. Special Effects: –

In the last 50 years Visual Effects and Special Effects have had a very close line according to a large number of the public who don’t work or spend a lot of time indulging films; to the rest of us it’s fairly simple:

  • Visual Effects = computer generated.
  • Special Effects = real life effects.

In a recent workshop with Jon Holmes, we delved into VFX and its uses, when to use it and what VFX can’t do. Myself and the rest of the class looked at applying a texture onto a moving object within 3D space which is one of the basic steps that opens up many doors to you. This sort of knowledge is what can really help the convergence task flourish, the only limit is your imagination.

 

History of VFX: –

Voyage Dans La Lune, is one of the oldest examples of VFX, it’s incredible that the following video was created nearly over 115 years ago. As dated as the film looks I personally feel that it still really holds up and does’t spoil the film or feel like a cheap gimmick. At the time this would have been something to get exited about, however now-a-days computer generated visual effects seems to be infesting movies; however we will look at why CGI has a negative stigma surrounding it and why it really isn’t that bad.

I won’t lie to you, I am guilty of being swept up by the uneducated public of just spewing all sorts about CGI and why its the worst thing to happen since sliced bread. Wait, that’s not how it goes… Anyway, CGI has this really negative image at the moment that it’s only used to create stupid looking gopher’s in Indiana Jones and the Kingdom of the Crystal Skull or to throw a Transform across a city in the latest Michael Bay blockbuster. I don’t see that the case anymore; after dicussing VFX, creating some of my own and watching behind the scenes of various movies I have seen the true power of CGI and why we went to hate it. Because bad CGI is all we see, where as good CGI you barely notice, which to be fair is doing its job correctly but to the uneducated the word ‘CGI’ just reminds them of all the crappy 3D models we have seen over the years. The following video by Freddie Wong, over at RocketJump explains this in more detail.

Pros / Cons: –

Pros:

  • Inexpensive
  • Allows more control
  • Allows creation of sets & characters that otherwise would be impossible

Cons:

  • Too much noticeable CGI can resort in audience feels a lack of authenticity
  • Time consuming
  • Can risk alienating your audience

 

Creating VFX: –

The first thing you are taught when it comes to VFX is motion tracking as its a fundemental skill that is needed to progress – it’s like trying to run without learning how to walk. It’s common knowledge to use a high shutter speed when filming your shots that will include visual effects, this is due to it allowing you to remove motion blur from fast movements helping keep tracking points visible for After Effects. Motion blur can then be re-added through the program where as removing blur from these fast movements is a lot harder to do. The following example shows the high shutter speed in action:

2D Motion Tracking Test ::: After Effects CC ::: The Grid on the Box from The Curious Engine on Vimeo.

 

I explored further with this method of working and began tracking a notification on an Android device, a new composition was created where I created a ‘WARNING’ graphic that would be displayed on the device. The same 4 point pin tracking process was used, helping show its expanding uses.

 

 

Tracking can also be used to stick images to other images, for example the following video by Jon Holmes, showcases a sky image that was replaced and then tracked onto a building near the horizon – another processes is used to help the houses and trees not be removed but instead be cut out and allow the sky to be placed behind creating the illusion of the sky being fully replaced.

Workshop1 ::: 2D Tracking ::: Sky Replace from The Curious Engine on Vimeo.

 Uses in the Convergence Task: –

I feel that VFX will be used a lot within the future of my one minute wonder short film, I will discuss this in the next VFX blog post.