Creating a Dynamic Wet Map Shader in Houdini

This tutorial introduces a new method for simulating wet objects, a shader-based method that first generates a 3D cloud of animated wet points, then by creating a shader that will use this data to shade the wet, previously-wet, or drying parts of the character that were previously in contact with a fluid. Software required: Houdini 14.
Course info
Level
Advanced
Updated
Jul 11, 2015
Duration
2h 18m
Table of contents
Description
Course info
Level
Advanced
Updated
Jul 11, 2015
Duration
2h 18m
Description

To realistically simulate fluids (water, blood, paint, oil, etc.), often a wet map is required to change the shading of an object where the fluid comes into contact with an object. These need to animate, not only while the fluid is active, but also afterwards to simulate drying. The usual solution, generating a wet map, or fixed set of images for a texture map, has several drawbacks: fixed resolution, color depths, and difficulties applying across objects or to subsequent shots in the film. This tutorial introduces a new method for simulating wet objects, a shader-based method that first generates a 3D cloud of animated wet points, then by creating a shader that will use this data to shade the wet, previously-wet, or drying parts of the character that were previously in contact with a fluid. This will be accomplished without any need to create or rerun the original fluid simulation. Software required: Houdini 14.

About the author
About the author

Jeff Wolverton has been working on visual effects for major motion pictures for over 15 years, having created signature effects for Sony Pictures Imageworks, Digital Domain, Rythym & Hues, Framestore, MPC, Disney, and Dreamworks.

More from the author
Section Introduction Transcripts
Section Introduction Transcripts

Introduction and Project Overview
Hi, everyone. My name is Jeff Wolverton. I'm a visual effects artist at MPC. Worked on a lot of movies over the years. Jupiter Ascending, Noah, Iron Man 3, Spiderman movies, superhero movies. In this course, we're going to learn how to create a dynamic wet map shader for residual wetness that's left behind on objects from a dynamic fluid simulation. Some of the key takeaways in this course are going to be how to make something look wet versus dry, and more importantly, when fluid interacts with an object, like an RBD object, how to make a shader for that object so that the wetness leaves behind, so once the fluid's gone, kind of a wet trail it leaves and then dries. There's a (mumbling) new method, a shader base wetness map. Not a wet map they normally have, it's kind of a new method, I've been working on inventing. Like paint splashes leaving a trail on an object, that kind of thing. So by the end of training, you'll have a full set up to create a shader space wet map system to augment your fluid simulations. I'm excited to work with digital tutors and share these techniques with you. So let's get started with the first lesson.