Extrude SOP - how to move objects with extruded faces by f@zscale

[Eyteneyer]

Hello Forum ,  i have a question. In project i need to put object on extruded face to move them together.

I've done this with just main "dist parameter(float)" myself just add simple expression to "transform Sop" in translate Y

It's work with little expression :
 bbox("../polyextrude ", -D_YMAX)-$YMAX+0.5   --- or ---  ch("../polyextrude4/dist")

But i go next level with this method and face to Wall of problem..  I try to extrude faces with distance scale "zscale"  i've create attrib with "attrib wrangle" and simple expression "f@zscale = fit01(rand(@ptnum), chf('min'), chf('max'));"

This works well, this expression move extruded faces randomly by Distance scale -  ptnum, but i need to put object on extruded face to move them together.  I try cople of methods but they didnt works.

Please Help.

Extrude_sop_zscale_dist_scale.mov

[Eyteneyer]

zscale_question.hip

[Eyteneyer]

I just wont all figures permanently stay on they scuare and control this behaviour with  "extrude sop" "distant scale".

[vicvvsh]

6 hours ago, Eyteneyer said:

I just wont all figures permanently stay on they scuare and control this behaviour with  "extrude sop" "distant scale".

Hello,

maybe is it worth to go the other way? I would made points at the center of each top primitive of the checkerboard after extrusion, and used copy to point sop. This way all figures will be always on top.

[konstantin magnus]

51 minutes ago, vicvvsh said:

I would made points at the center of each top primitive of the checkerboard after extrusion

Good idea. Here is an example using point instancing for better performance.

chess.hipnc

[Eyteneyer]

Wow!! Thanks a lot konstantin magnus!! If i do some tutorial for my youtube channel i put your name in discription! Good picture with tests!)))

[Eyteneyer]

Hello konstantin magnus! Is the any way to copy chess figures on points?

[Eyteneyer]

I've done this with "rivet" but its crazy)))

May someone know easy way to do such effect?

Edited September 26, 2019 by Eyteneyer

[konstantin magnus]

Hi Ilya, the instance geometry node offers a more usable approach : https://www.sidefx.com/docs/houdini/nodes/sop/instance.html

• Assign an arbitrary number of objects in a multiparm block.
• Then apply random choices to s@instancepath for random distribution.

int seed = chi('seed');

int inst_total = chi('instances');
int inst_num = int(rand(@ptnum + seed) * inst_total) + 1;

s@instancepath = 'op:' + chs('object_instance' + itoa(inst_num));
f@pscale = chf('scale' + itoa(inst_num));

chess_instancing.hipnc

You can read more about instancing here: https://www.toadstorm.com/blog/?p=493

Edited September 29, 2019 by konstantin magnus

[Eyteneyer]

Thank you again konstantin magnus but this randomise here, i need just a Spanish Opening in chess where figures on their squares should stay )