Hello and Animating multiple pieces of geometry using CHOPS

[moth0027]

Hello od[forcer] community,

I am new to the forum and pretty new to Houdini so I firstly wanted to say "hi!".

Secondly I have been working on a project which involves mosaic tiles on a wall moving in time to music (like a graphic equalizer). My tests with simple geometry have been fairly successful. I've been using a grid, creating an attribute for 'height'. Animating this attribute through CHOPS and copy stamping the outcome to box geometry. The final effect is the box geometry aligned with the grid points move perfectly in time to the music - cool.

The only problem now is I am bringing in the proper geometry and I'm a little stuck! I've tried two methods...

First method I'm using the trace node to create the exact shape of the (non-uniform) mosaic tiles and then extruding. I've also created a foreach node which takes the traced geometry, adds a centre point and deletes the rest - effectively I've got my geometry and now my grid of points. Only problem is now I have no idea how to go about assigning each tile back to it respective point once the height information has been applied. Of I use the copy node like before it duplicates my entire wall on each point rather then each individual tile.

For the second method I'm using the trace node again and rather then creating an array of points to animate the height attribute, I'm just using the geometry and trying to reapply the height to a transform node once the attribute has been processed in CHOPs. I'm not sure how to do this since before I was copy stamping the values, while this time just typing in the $HEIGHT directly in the transform node does nothing.

I know there must be a fairly simple solution to this - because my knowledge is still limited to a couple techniques I would really appreciate being pointed in the correct direction.

Thanks for all your help in advance,

Moth

[bloomendale]

Use Connectivity SOP to add point attribute (let it be default "class") with same value per tile. Then when you're creating center point promote that attrib to this point.

Add Delete SOP after your geometry before copy SOP and use stamp expression to delete all points with "class" attrib != this attrib on point you are copying to.

3ak_copyTiles.hipnc

Edited June 25, 2012 by bloomendale

[moth0027]

Hello Bloomendale,

Thank you for your quick response and test file.

I have not used the Connectivity SOP before... or used a stamp function in the same way you demonstrated... or used the detail() expression you used in the foreach node!

There really is so much to discover and learn in Houdini - it's an amazing application!

I shall dissect your file and get my head around it and... all going well post a test render shortly.

Thanks again, I really appreciate your help!

Moth