JuWeiFan
Wang

FX Artist

Week7 Particle And pyro trail

Update: 6/25/23

Thesis Committee's suggestion Base on the week 2 result

Base on the suggestion, I add the link for the reference I used.

Week 1

Week 2

My idea is that there will be blue smoke and particles around the water god, and the water god itself will also transform into linear particles similar to the shape of water flow

Process Part 1
water gad trail setting

Camera movement setting (shot one) base on the committee's advice I use this shot

Anchor 1

After replacing the ball with a Model figure, it is found that the character will only translate on the curve

use the wrangle can mkae the model follow the curve's normal

Process the wiring of the model, make sure it will evenly spread (remesh node)

for this model I kind worry that only make this model become pyro source is not enough, I might add other source later.

this way is not working cause I boolean the model, after I deform the geo, the wire become mess.

the model's eye and hand need to be adjusted to make sure the model is closed and not overlap

pyro

add pyro source node : particle separation: 0.05, density attribute

add volume rasterize attribute node :

also add velocity blur. base on that add trail node to compute velocity(Now it looks like it's moving forward at full speed)

next create dopnet work. pyro object, solver, and volume source

remember to click the Enlarge Fields to Contain Sources, it can create the bound base on the SOP path at first frame.

customize pyro velocity

before

after

Adjust the animation because I don't want the smoke trail too long. I also adjust the volume rasterize attributes' particle scale 2 and Dop level velocity's source scale 4 .

adjust the pyro length

Data Setting : Dopnet velocity scale: 0.5 substep: 2

substep need higher and I hope the smoke is more concentrated at the end

before

after

Data Setting : substep: 4 to see the result

Right now I like short trail better. After I finish other fx I will base on that and adjust later

Data Setting : substep: 4 , particle scale 1( long trail )

Data Setting : substep: 4 , particle scale 1 ( short trail )

Particle

The setting is the same as the pyro but add the attribute vop(in vop network, also create the animation to give the particle variance)

in dop network

first to get the particle date from the vop network that I just created and adjust the particle number from reference area( remember to click on the Scale Point Count by Area otherwise it won't work)

then set the particle birth rate add the variance for particle

for the setping issue change the interpolate source form None to Back

also change the match topology to point velocity(in case topology of the geometry change).

create trail to compute velocity.

the reson why it look like this is because my model is not moving in the first frame also the model inheriting the velocity from my model.

the solution is make the dopnet work simulation start frame become 3

and inherit velocity become 0

adjust the trail length (life expectancy 0.3)

particle with pyro

adjust vop

next I want particle move same as the pyro, create popadvectbyvolumes

base on the result adjust the smoke simulation, add gas blur and enable the control setting (gas turbulence)

also adjust the volume rasterize attributes(density) particle scale to 1.5

substep 2

There is a clear boundary in the middle of the smoke, the tail smoke is too scattered, and the substep is too low

change the model position, to make sure the velocity trail is thinner at the end of the smoke.

then change volume rasterize attributes(velocity) particle scale to 4

dop network velocity source scale 0.5

volume velocity scale 2.5 but for save time I change the voxel size to 0.4

change the voxel size to the 0.05(original)

recache the particle part

create the attribute wrangle to make the particle trail to have more variance (change the rotation and thickness of the trail,)

When the smoke collides with the mountain, the length of the smoke significantly lengthens, resulting in the animation of the smoke not appearing to accelerate significantly.

So I keyframe the particle scale(volume rasterize attributes (vel part)) from 4 to 16

Some particles rushed to the outside of the mountain due to their velocity. but after add rotation and change the thickness that part particle is gone.

particle of the upper body

Anchor 2

attribute noise

normal set up

base on the particle create the smoke simulation

density part

customize velocity (add volumvelocity)

cause the particle birth rate is really low, after the particle gone the smoke will base on the particle velocity keep moving(red part)

have to make the particle hold little bit longer(birth rate)

also use pop vop Multiply with constant(1.5) to make sure the smoke won't fade too close to the model

set up the collision of the model(base on the result above, the smoke will go through the body)

Vdb from Polygon and Vdb Smooth

volume source setting

the smoke is little bit flying up, so I adjust vop attribute

the same way to change to the particle result

add collision

Big problem (The model needs to be five times larger than it is now. After inspection, it was found that the upper body simulation needs to be adjusted)

the other one is that when I use the copy to point node the houdini crash everytime

1. after adjust

2. solution

about the crash problem

I use the attribute delete node to delete metrail before I add noise on the model, in that part , I also delete UV data. after I bring back the UV infromation the copy point node start to work.

Final result

Anchor 3

reference

https://www.youtube.com/watch?v=KTjV4ulyZUM

https://www.youtube.com/watch?v=yKwe8vLYgio

https://www.youtube.com/watch?v=_vTwmhrdWOo

https://www.youtube.com/watch?v=UuptVXQSCgc

Anchor 4

Bibliography

https://www.youtube.com/watch?v=aUMNWIn9gns

https://www.youtube.com/watch?v=mVN74ike5e

https://www.youtube.com/watch?v=yne_eDBlRcw&t=109s