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Flooding Stairs

Title: Flooding Stairs

Programs: Houdini

Modeled: Semi-Procedural Houdini

SIM: Houdini

Lighting: Houdini

Texture: Houdini

Rendering: Mantra

Description:

An exploration into Houdini 18 FLIP fluids, in order to replicate a real-life reference as closely as possible.

As of (3/27/20) is the reference video, animation, still frame render, flipbooks, and Houdini breakdowns.

Render
W20_V721_VuilliomenetLuke_floodingStairs
Animation
Particle Tank Prep
Reference
FLIP Tests
Particle Tank Prep
001_pTank.JPG

Flip tank settings

Particle Tank Prep
002_pTank.JPG

Unwanted particles are grouped by the collision volume and then blasted. This is done to make the SIM more efficient, as well as prevent particles being born inside collision geometry.

003_bound.JPG

Bounding object to ensure particles don't fall out of sim area.

Particle Source
004_pSource.JPG

A VDB, Surface Distance Field is created from the stairs, transformed and then intersected using VDB Combine to scatter points inside.

Particle Source
005_pSource02.JPG

Particles are scattered inside the volume. Afterward, their position is moved using various noise functions.

Particle Source
006_pSource03.JPG

Any points moved inside the stairs are grouped and deleted.

Particle Source
007_pSource04.JPG

Noise functions and various ramps are used to remove points at semi-random locations. As well as create a velocity vector.

Particle Source Top
008_pTopSource.JPG

The same process is repeated for the top source.

Particle Source Top Animated
Collision
009_collision.JPG

Collision geometry

FLIP Forces
011_forces.JPG

All forces

FLIP Forces
010_forces01.JPG
010_forcesBottom02.JPG

A box is created to define a region, while a mountain node is animated to create an undulating shape. Points are scattered inside the box, and then point vop is used to remove points and create velocity vector.

Finally the points are rasterized using volume rasterize attribute.

FLIP Forces
012_forcesGround01.JPG

Ground force

FLIP Forces
013_forcesMiddle01.JPG

Middle Stair Force

FLIP Forces
014_forcesTop01.JPG

Top Stair Force

FLIP Forces
015_forcesSink01.JPG

Edge Sink Force

FLIP SIM
016_FLIPSIM_NETWORK.JPG

FLIP SIM Network

FLIP SIM Settings
017_FLIPSIM_settings01.JPG
018_FLIPSIM_settings02.JPG
019_FLIPSIM_settings03.JPG
019_FLIPSIM_settings04.JPG
019_FLIPSIM_settings05.JPG
019_FLIPSIM_settings06.JPG
019_FLIPSIM_settings07.JPG
019_FLIPSIM_settings08.JPG
019_FLIPSIM_settings09.JPG

All settings for FLIP SIM

FLIP SIM Flipbook
File Version: 133
Core Fluid Mesh

What the Core FLIP fluid looks like after being passed through a Particle Fluid Surface node

020_fluidMesh.JPG
White Water Prep
021_ww_source01.JPG

The compressed fluid cache is passed to the White Water Source node to generate the needed volume.

The fluid compress created issues where part of the volume was packed below the surface of the stairs. When passed to the whitewater sim particles would jump from below the stair plane.

This was fixed by using the stairs as a second whitewater source and vdb combine (Subtract) from the fluid cache.

White Water Prep
021_ww_source02.JPG
White Water Prep: Emission
021_ww_source03.JPG
White Water Prep: Curvature
021_ww_source04.JPG
White Water Prep: Acceleration
021_ww_source05.JPG
White Water Prep: Vorticity
021_ww_source06.JPG
White Water Prep: Extra Volumes
021_ww_source07.JPG
White Water SIM
022_WW_SIM.JPG

POP Drag and POP Wind are used to break up the evenness of the SIM. It was found out that the new "Clump Density" controls in the Foam tab is needed to be either turned off or set to much higher neighborhood values to allow fine detail to persist.

White Water SIM

Settings

022_WW_SIM_settings01.JPG
White Water SIM
022_WW_SIM_settings02.JPG
022_WW_SIM_settings04.JPG
022_WW_SIM_settings03.JPG

Settings

White Water Flipbook
White Water Render Prep

Group separation and volume creation

023_ww_renPrep.JPG
Fluid Core Shader
024_shader_fluidcore.JPG
Fluid Volume Shader
024_shader_fluidVol.JPG
Foam Shader
024_shader_foam.JPG
White Water Shader
024_shader_whiteWater.JPG
Spray Shader
024_shader_spray.JPG
Railing Shader
024_shader_railing.JPG
Sign Shader
024_shader_sign.JPG
Signpost Shader
024_shader_signPost.JPG
Stairs Shader
024_shader_stairs.JPG
Ticket Machine Shader
024_shader_ticketMachines.JPG
Wall Shader
024_shader_walls.JPG
Wall Moulding Shader
024_shader_wallMoulding.JPG

All Rights Reserved as intellectual property

by Luke Vuilliomenet