Digital Assets_Group Expressions

[Justin K]

Hey all,

Very new to Houdini here. I am going through a simple project: building a basic model procedurally so that I can turn turn it into a digital asset.  Shout out to Gianvitto Serra and his youtube videos for instruction.  

 

             Here is what I am trying to do at this point.   I have a vertical tube with a slight controllable taper at the top.  As of now it has seven horizontal divisions and seven faces within each loop.  The shape is controlled by a line, a resample, and revolve sop, respectively.    Eventually I want to extrude every other loop, using a group or series of groups, and I want the groups to follow this logic: 

                      The number of faces in the loop changes based on the divisions within the preceding revolve node.  However the number of faces within each loop always corresponds to the number of divisions, and it is this relationship I want to take advantage of regulate and  generate the extrusion groups.  

              As I see it, I should be able to use this division value from the revolve sop as a relative reference within an expression based group to

                       1) get the total number of primitives per loop.

                       2)  call each primitives within that loop---->0,1,2,3,4,6,7.  

A simple premise I think, but my code knowledge is limited at this point (I am using Daniel Shiffman's channel and his work with Processing to help me get comfortable with the code needed

for visual processing, but the end goal is to be able to do things in houdini  

 

Once I get this coded, I think I can use this 'function' as the building block for additional groups, now using a pattern rather than full expression,  (group 1 is n group of primitives 0...7, now repeat this over and over for the length of the tube but skipped every other n).  

Any suggestions?   

And if there is any online resource that someone could point me too that would be helpful for group management and development that would be helpful as well---I am more interested in the structure of the problem and how to deal with it in Houdini rather than specific solutions-though that would of course be great.  

Here is the file.  The group is labeled in blue.  To the right I have the extrude pattern manually generated using in viewer selections that I want to control using code.  

 

Thank you.  

 

 

Lightningbolt_v002.hipnc

Edited December 21, 2016 by JKeil