I had initially wanted to put VFX everywhere in pretty much every scene of the movie. However to finish the movie off on time I was left with one and a half days to do all the VFX off. One and half days to do the effects for the whole movie = not going to happen.
Doing the VFX in super speed
Before even starting the VFX I still had to
- grade the movie,
- composite the effects and layers (it’s odd you spend so much time breaking everything into separate layers in 3D only to put them back to together in 2D)
- sort out the hologram effects,
- finalise all the GUI stuff
- sort out the credit list (fortunately I had some help from Craig with these three items),
- work with the sound designer
- do the dodo to mammoth transformation (a blog entry in itself) to do.
- render out the final edit (how many times will Premiere crash?), conform the movie
- burn the movie to disc case (this is fraught with danger) I wanted to also create some cool cover art for the disc (I didn’t really fancy going to bed this month anyway)
- and send it off to the festival (i.e get to the post office and hope there isn’t too long a queue)
I had about two and a half weeks to do all this before the deadline, I really needed the effects done super quickly. Fortunately being an effects artist as a day job you get used to starting and completing complex unplanned effects shots by the end of the day – only this time I was the producer setting these ridiculous schedules.
The spreadsheet knows best
To figure out how to do this I went back to the master spreadsheet and looked at all the shots that I could realistically put effects in (in a day and a half).
I categorised each shot as either an
VFX A – grade ‘A’ shot where the effects were essential to the plot
VFX B – grade ‘B’ shot where the effects would support the plot
Pretty much all the other shots would be a grade ‘C’ shot where I’d like to have effects in there.
Fig 1. I went through each of the sequences I split them up into FX A and FX B grades
Fig 2. It dawned fairly early that the snow around the mammoth would be the major area to focus on getting right.
This initial list gave me a total of 18 VFX shots of which it broke down into
11 grade As and
7 grade Bs
Time was running out (I had just spent half a day updating the spreadsheet J) pretty much all the VFX B particles had to be cut, I then had to focus on the most important VFX A shots.
I started on the Dodo Dust and the Mammoth Snow as I called them. As it was getting late I split the work thus
1 day on the simulation – I thought getting the particle animation right was most important
Half a day on the rendering – well rendering particles should be pretty straight forward, right? WRONG!!!
Particle Sim
Simulating the particles was very quick it’s just as well that this is my day job I managed to whizz through the simulation phase very quickly.
Video 01. with and without Dodo Dust and Mammoth Snow
I won’t go into any great depth on how to create particle effects there are many good tutorials for that. The basic set for the sim involved render type sprites on the particles.
I quickly set up some basic expressions to control the lifespan (lifespanPP means per particle lifespan), the scale (which used a ramp over its life), the twist and opacity (again using a scale) – again many sites that will go into the particulars of each data type for you (I recommend the particularly excellent digital tutors although other particular excellent sites are available).
Fig 4. Setting up some basic expressions on the ground snow
I threw in a couple of quick fields to add some turbulence and gravity, you can always use the relationship editor to see which fields effect which particles.
Fig 5. Adding fields can soon get out of hand, name them sensibly and use the Dynamic relationship editor (Windows | Relationship Editors | Dynamic Relationships)
Particle Rendering
The thing about working at the top post production companies as everyone who works in such places will tell you is that you have all these wonderful in-house rendering tools to render particles in amazingly quick and reliable ways. These are great but when you try to do the same thing at home alone you don’t have any of these wonderful tools and have to go back to basics.
For some odd reason I got a lovely alpha channel with the Mammoth Snow, but with the dodo dust I could only get the alpha of the small spots to render and not the dust at ground level.
To combat this I used a combination of the maya hardware renderer and the render buffer to get the job done.
Fig 6. The Maya Hardware renderer is fairly basic, considering the time I had available it probably wasn’t a bad thing as I didn’t have to navigate through a myriad of settings.
The even older school way of rendering out particles, which I’m sure no post production house uses anymore is the hardware render buffer. I used these back in the day when I matchmoved shots and had to render out wireframes and cones to prove the camera track – oh what fun it was…
Fig 7a. the hardware render buffer gives various controls to render out multi pass (for motion blurred particle effects) and various draw styles
Fig 7c. Here you can set the draw style, render your particles as points or smooth shaded (i.e. for sprites), you can also render out the whole thing as a wire frame.
Fig 8. All in all the hardware render buffer gave a fairly okay output, it was more the speed I needed to hit the deadline.
Still to do – time running out rapidly
All in all for a day and half work I think it came out quite well, by focussing on the effects that pushed the story forward I was able to stay on course (a course which involves no sleep for the next two weeks, but a course none the less). I could have spent a lot longer on polishing the effects and creating more effects for each shot, but as everyone who works in CG knows, you never really finish a shot you just run out of time…
Next step compositing and grading.
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