PolyExtrude in VEX

[Ryuji]

Hi, 

 

I've been wondering if anyone tried to recreate the polyextrude sop in vex? I'm particularly interested in the inset function of the sop, and how one would go about recreating this in vex.

 

Any ideas?

 

Thanks in advance.

[konstantin magnus]

Hi Ryuji, you can inset a polygon or polyline with these steps:

vector next = normalize( point(0, 'P', (@ptnum + 1) % @numpt) - v@P ); 
vector prev = normalize( v@P - point(0, 'P', (@ptnum - 1) % @numpt) ); 

vector avg  = normalize(next + prev);
vector up   = normalize( abs(cross(prev, avg)) );
vector in   = cross(avg, up);
float dist  = dot(next, avg);
vector dir  = in / dist;

v@P += dir * chf('extrude'); 

Kim Goossens discusses this here: https://www.youtube.com/watch?v=tnDqwcNG20Y

[Ryuji]

Hey Konstantin,

 

Thank you so much for this. It's really interesting.

I wanted to make a compilable version of polyextrude, but in the end, I used the polyextrude sop with local attributes (zscale, etc...).

My attempt at a compilable polyextrude was like 3 times slower than the normal one.