Hash Fellow robcat2075 Posted September 25, 2014 Hash Fellow Posted September 25, 2014 This is the start of some basic R&D on particles. Four different tests for "fluid" to see how it behaves and how it interacts with the objects it hits. FourWaters.mov Quote
detbear Posted September 25, 2014 Posted September 25, 2014 RC, Those are some really nice tests. Your particles must be larger than mine in my attempts. And the models smaller. Mine are life-size at this point. I guess that would help if I shrunk my set down. Quote
Hash Fellow robcat2075 Posted September 25, 2014 Author Hash Fellow Posted September 25, 2014 I'm finding there's a lot of interplay in the parameters that have a way of amplifying or negating one another so don't shrink her yet! Quote
Hash Fellow robcat2075 Posted September 26, 2014 Author Hash Fellow Posted September 26, 2014 Here are some more fluid tests, not all useful but interesting none-the-less. PRJ06Tests.mov Quote
zandoriastudios Posted September 26, 2014 Posted September 26, 2014 A big part of the look of water is going to be the environment that it reflects and refracts. Rather than coloring the surface, try puting a skydome around it. Quote
Hash Fellow robcat2075 Posted September 26, 2014 Author Hash Fellow Posted September 26, 2014 Mostly I'm just coloring these tests so i can see where all the droplets go easier. I'm still investigating basic settings for their effect on particle behavior. What I'm finding so far... The "Droplet Physics" has two parts, Pressure Force and Surface Tension Force. The droplets are imagined as spherical particles that can move independently of each other but Pressure Force and Surface Tension Force influence their interaction with each other. Pressure Force controls how much their spherical boundaries are allowed to overlap. If Pressure force is set to zero it is possible to endlessly pour particles on top of other particles and the volume of the liquid will never increase, the particles can overlap completely. When Pressure force is greater than zero the particles will begin to nudge each other aside and begin to stake out their own personal space with less overlap. If particles are born closer than their Pressure Force setting allows or if they collide and end up too close together they seem to spray apart from each other. Higher values make for lumpier, more churning liquids. Surface Tension Force is the tendency of particles to attract to neighboring particles and form a larger droplet Quote
Hash Fellow robcat2075 Posted September 27, 2014 Author Hash Fellow Posted September 27, 2014 Seen while waiting for the first frame to calculate... Quote
detbear Posted September 27, 2014 Posted September 27, 2014 Yeah... And making even the most tiny changes in any of those perameters you mentioned above will result in a drastic change in the fluid behavior. It's a beast. Quote
fae_alba Posted September 28, 2014 Posted September 28, 2014 Seen while waiting for the first frame to calculate... time.JPG I had time estimates on processes I've been writing for work....kind of got smacked down when the powers that be heard them. "Get them down to 1 hour!" was what I heard. What's your solution to trimming the seconds? Quote
Hash Fellow robcat2075 Posted September 28, 2014 Author Hash Fellow Posted September 28, 2014 I had time estimates on processes I've been writing for work....kind of got smacked down when the powers that be heard them. "Get them down to 1 hour!" was what I heard. I recall reading that in the early years Pixar had a goal of no more than 5 minutes render time per frame. They've blown way past that on more recent projects but there was a time when that was their practical limit to get the movie done on time. What's your solution to trimming the seconds? Basically you try to swap in faster things that will do the job of elaborate things. For example, it's unlikely I will use particle fluids for the lagoon that submarine is in, I'll probably use my "cloth" water which is pretty fast to work with and will look appropriate. Somewhere in my tuts is a thread where I went through a shot that someone said was taking too long ans showed various alternate techniques to make it spit out faster. Quote
fae_alba Posted September 28, 2014 Posted September 28, 2014 Excellent answer Robert! Too many times we try to use the spiffiest solution just because we can, failing to realize that all that really matters is how it looks in on screen in the final cut. Read an article once that when the producers at Pixar (can't remember which movie) wanted a water splash effect, he decided to just go out to a pool, film it, then place that into the clip. Quote
Hash Fellow robcat2075 Posted September 28, 2014 Author Hash Fellow Posted September 28, 2014 Read an article once that when the producers at Pixar (can't remember which movie) wanted a water splash effect, he decided to just go out to a pool, film it, then place that into the clip. Along the same line, in the original "Madagascar" many of the background cityscape buildings are not CG, they are physical models painted and photographed to look like CG and used as "rotoscope" behind the character animation. They did this because they didn't have the computer power to render all that. I'm surprised by that but that's what they said in the commentary to "Madagascar II" Quote
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