VFX: No1. Aircraft in near-miss with a building

At the request of rockgem in this discussion:

http://www.cgpinoy.org/visual-effects-tutorials-vfx-f100/discussion-what-do-you-guys-want-to-learn-or-see-t3291.html

I will be posting a series of commentaries about some of the scenes that my team worked on in the past.

The first in the series (I will not mention the title at backgrounder kasi hindi pa siya released) will be a scene involving an aircraft flying low altitude above a city somewhere. We do not like to imitate 9/11 not to mention be a reminder of that holocaust. So rather than opt for a full crash, direction lead to only the tip of the wings hitting the glass walls of the building. Isa pa, baka mamatay ang bida!

Bale ganito ang ideya, these type of previews are called animatics - it doesn't have to be elegant, the pupose of the animatics if to have visual clues as to what might be happening in a particular shot, what elements will be in, this is also a tool for those involved in production to give them the idea of what has been accomplished to date, the animation timing and what might be added or removed to make the shot more effective. Think of the animatics as a drowing na puro tingting. Its a waste of time to put in all elements that might be disapproved by the director for wrong timing - or for simply being a distraction. So for animatics - make it simple!



C130 WING TIP hits the building Animatics from the vertexwrangler on Vimeo.


And here's a quick preview of what you might expect (this is a preview render - meaning there are elements not included here that made it to the finished shot - isa pa wala pa itong Color Grading (color correction in laymens' term)


C130 WING TIP hits the building In-Progress Preview from the vertexwrangler on Vimeo.

So ano po ba ang unang ginagawa kapag may assignment na ganito (sa totoong buhay ha):

Unang una, pagkabigay sa akin ng BG plates*, magkakaroon ng brainstorming o pag-uusap ng vfx director (kliyente) at ng aming team sa aking pangunguna. Pag-uusapan dito kung ano ang intensyon ng scene at kung anong elemento (elements - basag na salamin, usok, concrete, sparks, etc) ang kinakailangan gawin.

Pagkatapos makipag-diskusyon sa VFX director, kailangan ko namang pag-isipan kung sa anong pamamaraan ko gagawin ang lahat ng elemento. Kasama na dito ang schedule. budget, tools and that includes software and hardware, at kung sino-sino sa aking mga team members ang mag-sasagawa ng ibat-ibang parte ng cg shot. Ito ang tinatawag na R&D at Pre-Production lalo na kung wala pa kaming workable solution - meaning kailangan pa namin na mag sagawa ng mga tests.

So uulitin ko: Ang kailangan gawin na elemento at process:

1. Track the camera movement so we can add demolition elements to actual 3d objects. Without a good track, the scene and all those bits and pieces will be useless.

2. Make the necessary 3d models - that included the aircraft and a rough 3d representation of the building.

3. Particle effects for the exploding concretes and glass, sparks, and smoke (we will use a separate particle renderer for smoke elements)

4. Render in multipass

5. Composite in After Effects

6. Make the client happy

That's more less about it. Please be reminded that I won't be discussing much about how to use a Tracking Software or how to model or how to operate Particle Flow. This document will be like a diary. An informal discussion on what went on during the development of the above cg shot.

I would also assume that you already know your way in MAX. That part of the equation will be something you'd need to work on although I am open to questions. My role here will be to explain how we might mix A+B+C so that we can achieve the director's goals.

The first lesson I always tell my friends here at the shop - CG might be intimidating or it might give you some kind of a high the first time. To make CG effective, it has to be transparent as if it's not there. There must be a reason for it's being - it must must help sell the story - if not then it will just be a distraction and your viewers will leave the theater wondering what the movie was all about.

I tried my best to write in a mixture of tagalog and english, I hope to continue writing this way in the future - I know it isn't perfect, anyways I am not in the business of writing tuts - I'm into CG

Until next installment. Have a blessed Sunday.[i]

Wow sir V ayos tong ginawa mong tuts, thanks for sharing. combination of multiple software... yung motion tracker po sa after effects ang ginamit nyo sa fake building and some of the added effects by creating a null object dipoba? nabasa ko lng po sa isang website yung motion tracking lalo na kug magalaw yung pgkakakuha ng video scene. yung particle system slike smoke and glass sa after effects din poba? yung plane and building sa isang 3d software? haay dami pa palang dapat matutunan. thanks po for sharing Sir V

Thanks for the kind works. Tracking was done in (3d) Syntheyes because of the 3d nature of the camera moves. The rest of the elements like smoke and glass including the aircraft and the building we did in 3dsmax. The smokes were Particle Flow and rendered using a dedicated particle point renderer.

waahhh...!!! and I thought I can keep up with your tutorial sir...

dude V!

eto ung mga trip kong work!!!!!

salamat sa mga guide at insights, laking tulong....

Wow thanks for indulging me on my request sir V and i have to say you are quite a generous man. I have tons of questions in my head right now but i'll just ask about multipass rendering first.

Based on this shot and more specifically the plane, what type of passes are rendered out and in what order are they composited in after fx? is there really a rule as to what blending modes should be used for a specific pass? is it also necessary to render in passes for particle elements such as smoke, dust, debris, explosion, etc.? i'm just curious since i've seen some vfx demos that have so many layers in them and each layer have different passes. Again thanks for this sir V and looking forward to bouncing ideas with you.

rockgem wrote:Wow thanks for indulging me on my request sir V and i have to say you are quite a generous man. I have tons of questions in my head right now but i'll just ask about multipass rendering first.

Based on this shot and more specifically the plane, what type of passes are rendered out and in what order are they composited in after fx? is there really a rule as to what blending modes should be used for a specific pass? is it also necessary to render in passes for particle elements such as smoke, dust, debris, explosion, etc.? i'm just curious since i've seen some vfx demos that have so many layers in them and each layer have different passes. Again thanks for this sir V and looking forward to bouncing ideas with you.

Although I intended to illustrate the passes in later installments, I'll try to list it here based on what I remember ( I don't have the ae files with me now). Here goes:

Parts were divided as follows, (a) the plane; (b) propeller; (c) the building; (d) contact elements - these are the debris, smoke, etc

Elements:

Diffuse pass Straight
Reflection Additive/Screen
Refraction Additive/Screen
Specularity Additive/Screen
Self-illumination Additive/Screen
Global IlluminationAdditive/Screen
Lighting Additive/Screen
Shadow Straight or Multiply
Ambient Occlusion Multiply
Multimatte (for selections using RGB)

I really do not follow a general rule as to which layer goes on top or below - It simply depend on a particular scene. In this case the additives goes above a Multiply. Also there are some issues to follow when compositing in 32 bits wherein linear renders should and must be composited additively - Multiplying layers will definitely cause alpha edges from becoming more prominent.

How a shot should be broken into is something the cg director should decide - in this case I separated the propeller into its own pass so that the compositor will have more freedom during color correction. Since this is basically a dark night shot - we needed to be able to make on-the-spot revisions as to the look and general illumination levels of the propeller-something hard to decide during rendering. It is very important to allow the most critical decisions to be made during compositing - and it would be impossible to do if the elements were not properly segregated.

As for smoke and dust - I usually divide them into three or four passes, so that we can lessen the thickness when the director decides to or add more if he wishes to during compositing. Some people might do everything in one pass but I personally think that it will pose more problems as it does not provide more freedom for the director in later stages.

As for Multimatte layers - basically this is just a mask of areas that might be subject to further comp edits, rather than create one mask for each part in B&W, Multimatte allows us to render masks for three distinct objects one for each RGB Channel. This can then be used in after effects using Channel selections.

Although we provide GI passes - sometimes it can done without it just by using the RawLighting Pass/ Ambient Lighting. I will discuss further use of this process with Ambient Occlusion in future post, perhaps in another thread.

I hope I have covered enough at the moment. I will post a screenshot of the composition sometime later, I might have missed a thing or two in the above list but its more or less like it I believe.

torvicz wrote:dude V!

eto ung mga trip kong work!!!!!

salamat sa mga guide at insights, laking tulong....

I know you always wanted to do these kind of stuff. I think the only thing stopping you - is not actually doing it. It's about time - don't you think so?

Bookmarked! Thank you very much sir V. That was more than enough and you really know how to feed one's mind. I will be digesting all of these in the next couple of days. I definitely need to experiment on the compositing side of things.

Assuming that we now have a good track, the models are done and ready. So I'll start the next installment with Particles and how they played a role in this shot.

In the meantime, I'll take a smoke - and sleep. Until next time.

i'm just appreciating this one. really haven't gone this far yet. though someday. this is an inspiration... tnx sir v for sharing this.

Need more rice to gain a level, thanks for sharing V. Now i know why movies take too long to compose, it needs a lot of passes to render for CG effects and every detail counts specailly if the scene is too close to the camera. whew need to learn more... thanks again THE V

@wenz3d i feel you bro. we need more people like sir V in this forum... hmm maybe we can clone or instance him. hehe

rockgem wrote:@wenz3d i feel you bro. we need more people like sir V in this forum... hmm maybe we can clone or instance him. hehe

You guys certainly know how to make sipsep! You cannot clone the vertex - but you can reference copy him.

v_wrangler wrote:Thanks for the kind works. Tracking was done in (3d) Syntheyes because of the 3d nature of the camera moves. The rest of the elements like smoke and glass including the aircraft and the building we did in 3dsmax. The smokes were Particle Flow and rendered using a dedicated particle point renderer.

thanks sir for sharing us this tut, wala akong masabi kung hindi papuri. sana po makayanan rin po nmin gumawa ng ganyang peice. wag sana kayo mgsawang magbigay supporta sa amin... thank u po