Tag Archive for: Tutorial

Maya HDRI Studio for Redshift

A video documentation on how to use the tool.

Houdini Houdono | Simulation – Episode 3 – RBD Balancing Pebbles

It’s Episode 3! In this video, I’ll show you how to set up a simple RBD simulation in Houdini and this time, as you’ve asked for it, I’ll cover the Redshift rendering setup too! I planned to keep the videos short, but to include the rendering setup, I had to add 10 minutes to the video length. Let me know if you prefer for me to cover the rendering setup each time, or simply focus on the simulation and keep the video bite-sized. As always, if you don’t know the basics of Houdini, check out Houdini Isn’t Scary: https://www.youtube.com/watch?v=Tsv8UGqDibc See you next Friday!

https://www.youtube.com/watch?v=Iw0SsBdXXQo

Houdini Houdono | Simulation – Episode 2 – Easy Disintegration

Welcome back to the series in Episode 2. In this video, I’ll show you how to create this classic particle disintegration effect in Houdini. I hear some of you will like a render setup portion to the video, but I wonder if it’ll make the video too long for you guys, let me know! In any case, I’ll try to incude that in Episode 3 and see how it goes ya? As always, if you don’t know the basics of Houdini, check out Houdini Isn’t Scary: https://www.youtube.com/watch?v=Tsv8U… Otherwise, have fun and see you next Friday!

Houdini Houdono | Simulation – Episode 1 – Particle Trails

Here’s a 10-part mini tutorial series to serve as bite-sized introduction to Houdini’s simulation tools. Let’s start easy for Episode 1 – Particles. If you don’t know the basics of Houdini, check out Houdini Isn’t Scary: https://www.youtube.com/watch?v=Tsv8U… Otherwise, have fun and see you next Friday!

Iridescent Glass Material in Redshift

Developed this iridescent glass shader in Maya / Redshift based on IG @odddough ‘s request at work.

  1. Start with the Redshift “Glass” present.
  2. Create a RS Fresnel and remap its values into rainbow hues.
  3. Optionally, if you’ve used MASH Color to have varying colorSet values for each part of your geometry like this toy gun example, you can add a Redshift Color Correction to this resulting information, remap colorSet to 0 to 360 and use it to drive the hue variance of the Color Correction node.
  4. Feed the resulting information into the refraction color of the Glass Material
  5. Increase the Dispersion Abbe number to 1 or 30 to taste, it creates iridescent refraction
  6. Enjoy the results!
An example of what this material can achieve.
The lighting setup for this example render. Some volumetric atmosphere and a couple cylindrical mesh lights with volume contribution
Iridescent Glass Material Shading Network
Screenshot of my screen as I was working on this material. While the render at the start of this post has some simple compositing, from this screen shot, we can tell that it looks pretty good right off the bat, without any comp work.

Create File Cache and File nodes in Houdini

Here’s a tool to add filecache and file nodes to your selected node in SOPs geometry context. At Masonry Studios, we base our Houdini geometry caches and its version on the file name (which contains the version number) and the node name, which is the default in Houdini’s file cache node.

However avoid using the file cache’s “Load from Disk” option to load the geometry back in, because:

  1. It’s convenient for the file cache node’s “Geometry Path” to stay as the default un-evaluated relative path, in order to generate new caches based on the current file version
  2. If we load in the geometry based on this relative path, and we version up our working file, this relative path will fail.
  3. Hence, we find it quite an elegant solution to use a file cache and a file node separately. The file node points to the absolute evaluated “Geometry Path” of the file cache node and we’ve since successfully avoided the issue of broken links to caches.
# Author: Ronald Fong
# Date: 29 Sep 2021
# Usage: Add this as a shelf tool. With a SOP node selected, use this tool to quickly create a filecache and a cache node.
# Feature 1: Names the cache nodes based on your selected node
# Feature 2: File node will automatically be the evaluated absolute path of your filecache node
selected_node = hou.selectedNodes()
geo_node = selected_node[0].parent()
name = str(selected_node[0])
filecache_node = geo_node.createNode("filecache", ("filecache_" + name))
file_node = geo_node.createNode("file", ("file_" + name))
file_node.setInput(0, filecache_node)
filecache_node.setInput(0, selected_node[0])
geo_node.layoutChildren()
filecache_node.setDisplayFlag(1)
filecache_node.setRenderFlag(1)
filecache_node.setSelected(1)
filename = filecache_node.parm("file").eval()
file_node.parm("file").set(filename)

RBD Packed and Vellum Interaction

Vellum and RBD both have the newer packaged workflows, and while it’s nifty on their own, I haven’t found a way to set up such that they can mutually affect each other properly in a single simulation.

Usually, we’d set this up in a custom dopnet using the multi-solver, but because of the way the packaged node’s geometry and constraints are group together, there’s no straightforward set up setting this up.

So here’s a quick and dirty (but efficient) way to fake the interaction between RBD packed simulation and a Vellum simulation.

The Result

The idea is to first mimic the movement we’d want of the interaction using just the RBD bullet solver. We feed that output to serve as a collisions geometry for another temporary Vellum solve, feed this temporary Vellum output back to a new RBD bullet solver for the final RBD simulation, and once again feed it back to a new Vellum solve for the final vellum interaction.

This multi-phase simulation approach yields decently convincing results. While it’s not technically accurate, it’s artist-friendly to utilise the packaged simulation nodes.

Node Tree

This screenshot of the node tree shows how Vellum and RBD packaged SOP level nodes feed into each other to arrive at the illusion of interaction.

Tag Archive for: Tutorial