Hello,

I've just watched a tutorial on vimeo on how to use music to derive deformation amount on geometry using CHOPs (https://vimeo.com/159852217) [vimeo.com] I'm wanting to use the same concept but instead of deforming geometry, specify the power of the explosion from the music, but I'm not sure how to go about that.

Thanks!

One simple way would be to use the chop to drive a color value on your source ( in this case you could start with points for example ) that's clamped from 0-1 (black and white) and then use that in your fluidsource as fuel. As long as you have temperature you're fuel should burn as its being emitted in more or less.

Then with that setup I would iterate further as needed.

below I posted a basic hip file to show you what I mean.

You can see on the right is the template points that are the fuel source and as they turn white they emit more fuel. ( changing your burnrate will give you some definitely more interesting results too)

Post the final work when you're done we would love to see it

Nico

hipfile post.

Sugleris
hipfile post.

Thank you Sugleris! I'll try that and let you know!

I'm a bit new to Houdini so please bear with me I think I understood most of your workflow but I have some questions:

1) what does this code do? “@Cd.x*5;”

2) Would I be able to replace the noise you created with the music chop created in the tutorial?

Thank you again!

1. @Cd.x * 0.5 means take the incoming x component of the Cd vector3 point attribute and multiply by 0.5.

It is very common to always MMB (MiddleMouseButton) on the upstream input node's icon to see what attributes are on the geometry. From there you can wrangle any of those attributes. MMB on the input to the Point SOP shows that there are a few attributes, one of which is the point type Cd. Cd is the name and 3fc means three float color type attribute.

2. Absolutely! But in the spirit of “don't delete nodes”, use a switch CHOP inserted after the Noise CHOP and then add the nodes to process audio and wire in as well then switch between the two until you know things work.

The first step is to add a File CHOP, fetch in your .mp3 audio file, append an Envelope CHOP, append a Math CHOP and range it to where you want and there is a simple audio intensity channel to get going quickly.