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About this tutorial
This tutorial will introduce you to the basics of Houdini’s Rigid Body Material Based Destruction workflow using the RBD Bullet Solver SOP. It assumes at least a beginner’s understanding of Houdini. Topics covered will be:
Preparing geo for destruction
Using the RBD Material Fracture SOPs
Bringing in a custom hitting object
Organizing your network for best workflow
Tweaking constraint and material properties
Creating intra-material constraints
Using multiple constraint types
Configuring glass for rendering
Debugging and tweaking simulations
Before you begin
This is a guided tutorial. This means a lot of tedious button pressing has been automated, so you can concentrate on setting properties and values that make a difference.
You can only do this tutorial from inside Houdini. You must display this page from a running Houdini session, just as you would load example files from the help docs.
To start, press the Load button below to load the required Houdini Digital Asset into your scene. The HDA contains a node that has buttons, which will create nodes a few at a time for you. At any time you can build the finished network in its entirety to see how it is supposed to work.
After you've finished this tutorial, it would be a good idea to start again, and try to do it by yourself from scratch with only the text in this page to guide you. If you want, you can run two Houdini sessions side-by-side (and copy and paste nodes from one to the other) to help you through it.
At the end of this tutorial, you should have a simulation that looks something like the animated gif above. However, it’s important to note that your simulation may not be identical, due to various reasons:
Minor changes to parameter values can have large changes to a simulation.
Software updates between when this tutorial was written and when you do the tutorial might introduce changes to behaviors.
Rendering with motion blur can introduce changes to your simulation.
Remember to save your scene file frequently as you work. For example,
Any value in the Houdini parameter interface that’s in BOLD is not the default value. To return to default values, right-click the parameter or folder and choose Revert to Defaults.
Load Digital Asset and Explore
Load the digital asset by pressing the Load button above. This will create a new digital asset for you called RBD Material Fracture Tutorial. The parameter pane will show buttons that are grayed out.
The Load button will only open the file if you are running a help browser from inside Houdini.
rbd_mf_tutorial1 node to dive inside, and you will see a node network that looks like this.
wall object, (or select it and press Enter) to dive inside to the SOP level. Here you will see the finished node network. If you turn the display flag on the last SOP in the chain (
rbdbulletsolver1) and press in the playbar, you will see the wall get destroyed by the hitter object.
It will take a few minutes for the various RBD "materials" (glass, wood, and drywall) and constraints to be built before the scene will begin playback.
The Wall Asset
wall object you will see a Subnetwork SOP called
wall1. Double-click this SOP to dive inside.
This wall is built simply so that we have some light-weight objects to work with. Here are a few things to keep in mind when building geometry for destruction:
Do not allow the geometry to intersect.
All geo should be “manifold” (meaning “water tight” or without holes). This is why there are numerous Polyfill SOPs in this network. If there are openings in the geometry, this node will fill them, (this often happens after boolean operations). If there are no openings, it will simply do nothing.
Each type of material is grouped. You will see how useful this is later.
To get out of this SOP and back up one level, press U or click the level up in the network editor path above the network view.
See Introduction to Material Based Destruction Tutorial for the step by step tutorial.